epidemiology research

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Advancing the science of communication to improve lives

What Is Epidemiology?

Epidemiology is the branch of medical science that investigates all the factors that determine the presence or absence of diseases and disorders. Epidemiological research helps us to understand how many people have a disease or disorder, if those numbers are changing, and how the disorder affects our society and our economy.

The epidemiology of human communication is a rewarding and challenging field. Much of the data that epidemiologists collect comes from self-report—from answers provided by people participating in a study. For instance, an epidemiological study may collect data on the number of people who answer, “Yes” when asked if someone in their household has trouble hearing. Each person providing such an answer may interpret “trouble hearing” differently. This means that the results of such a study may be quite different from a study in which actual hearing (audiometric) tests are administered to each person in a household.

Also, many epidemiological estimates try to determine how the number of people affected by a disorder changes over time. The definition of a disorder also tends to change over time, however, making estimates more difficult. Even scientists working in the same field at the same time may not agree on the best way to measure or define a particular disorder.

Key terms to know in this field are: 

• Incidence: The number of new cases of a disease or disorder in a population over a period of time.
• Prevalence: The number of existing cases of a disease in a population at a given time.
• Cost of illness: Many reports use expenditures on medical care (i.e., actual money spent) as the cost of illness. Ideally, the cost of illness would also take into account factors that are more difficult to measure, such as work-related costs, educational costs, the cost of support services required by the medical condition, and the amount individuals would pay to avoid health risks. (Adapted from the Environmental Protection Agency’s Cost of Illness Handbook )
• Burden of disease: The total significance of disease for society, beyond the immediate cost of treatment. It is measured in years of life lost to ill health, or the difference between total life expectancy and disability-adjusted life expectancy (DALY). (Adapted from the World Health Organization .)
• DALY (Disability-Adjusted Life Year): A summary measure of the health of a population. One DALY represents one lost year of healthy life and is used to estimate the gap between the current health of a population and an ideal situation in which everyone in that population would live into old age in full health. (Adapted from the World Health Organization .)

Epidemiology

Studying populations to improve healthcare

Epidemiology research improves the health of patients and communities by identifying and addressing the cause and control of diseases and disorders within groups of people.

Epidemiology is foundational to clinical and population sciences research and central to Mayo Clinic's mission of improving health. Mayo Clinic's Division of Epidemiology aims to improve clinical practice and population health through innovative, multidisciplinary and methodologically rigorous research across the translational research continuum. The division is nationally and internationally recognized for excellence in translational science and education. Building on a legacy of exceptional epidemiologic research, we are uniquely positioned to address urgent clinical and population health questions across the full translational research spectrum. Our ongoing research programs focus primarily on complex diseases including cancer, cardiometabolic diseases, neurologic diseases and musculoskeletal diseases.

Most studies conducted within our division are funded by the National Institutes of Health and focus on clinical, family and population-based studies. These include the Rochester Epidemiology Project , which is a medical records-linkage system containing persons residing in 27 counties of southern Minnesota and western Wisconsin. The division also is home to the Survey Research Center, which serves as an institutional resource for conducting mail, web and telephone surveys for research purposes or clinical care including remote patient monitoring.

Part of the Department of Quantitative Health Sciences at Mayo Clinic, the Division of Epidemiology is made up of more than 100 members with doctoral-, masters- or bachelor's-level expertise. The division is represented at all Mayo Clinic campuses in Minnesota, Florida and Arizona.

• Division chair: Lila J. Rutten, Ph.D.
• Administrator: David M. Moertel, M.B.A.
• Operations manager: Jolaine M. Hines, M.S.

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Read recent news stories highlighting research in the Division of Epidemiology.

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What Is Epidemiology?

For many people, the COVID-19 pandemic was the first time they’ve been exposed to the idea of an uncontrolled disease—introducing phrases like “transmission,” “incubation period,” “contact tracing,” and “herd immunity” into the public vernacular. But for those in the field of epidemiology, these ideas are at the core of their careers, and a pandemic is exactly what they’ve been preparing for. Epidemiologists have historically performed vital work to protect and improve the health of populations, whether it is neighborhoods, cities, countries, or continents.

Epidemiologists are crucial in mapping and understanding the effects of the coronavirus, but their work extends beyond novel viruses and pandemics. So, what is this unique field? And how do epidemiologists approach issues in public health?

What is epidemiology?

Epidemiology is the foundation of public health and is defined as the study of the “ distribution and determinants ” of diseases or disorders within groups of people, and the development of knowledge on how to prevent and control them. Epidemiological research helps us understand not only who has a disorder or disease but why and how it was brought to this individual or region. One of the earliest instances of modern epidemiology can be found during an 1854 cholera outbreak in London . Doctors believed the widespread illness must have been airborne, but Dr. John Snow, widely considered to be the father of epidemiology, employed a different kind of thinking. By carefully mapping the outbreak and analyzing those who were infected, Snow was able to link every cholera case to a single water pump at the intersection of Broad and Cambridge Streets (now Lexington Street) in London’s Soho neighborhood. The removal of the pump stopped the disease in its tracks—laying the basis of today’s epidemiological practices.

Today, epidemiologists use the insights gathered in their research to determine how illness within a population affects our society and systems on a larger scale, and in turn, provide recommendations for interventions, such as removing a fatal water pump.

As the novel coronavirus became widespread, epidemiologists around the world worked to control the spread. Our research spans work to better understand the virus and how it is transmitted; to project its spread and identify vulnerable communities; to develop diagnostic tests and therapies; and, to assess the U.S. and global health systems’ preparedness.  See examples of our faculty's work with COVID .

Types of epidemiology

Epidemiology can cover a wide range of issues, from unintentional injuries to psychosocial stress. Here are a few areas in which Columbia Mailman faculty and students work:

Infectious Disease Epidemiology for Public Health  This type of epidemiology is at the forefront of today’s world—as epidemiologists work on the front lines to track and trace the spread of COVID-19. In this concentration, infectious disease epidemiologists work to detect pathogens or viruses, understand their development and spread, and devise effective interventions for their prevention and control.

Chronic Disease Epidemiology Chronic disease epidemiologists  battle day-to-day chronic conditions such as cancers, diabetes, obesity, and more. Epidemiologists in this fieldwork to research the origins, treatment, and health outcomes of these diseases in the fight towards prevention.

Environmental Epidemiology Environmental epidemiology focuses on how an individual’s external factors affect health outcomes. This includes physical factors like pollution or housing, as well as social factors like stress and nutrition. Environmental epidemiologists work to understand how different environments may result in physical or neurological outcomes, ranging from psychiatric to cardiovascular disorders. 

Violence and Injury Epidemiology This epidemiological focus aims to address unintentional and intentional injuries across a lifespan. For example, epidemiologists in this field might focus their research on car accidents and work to identify the associated risk factors. Armed with extensive research, the goal of violence and injury epidemiology is to improve a population’s health by reducing the morbidity and mortality rate from unintentional and intentional injuries.

How epidemiologists track diseases

Epidemiology centers around the idea that disease and illness do not exist randomly or in a bubble. Epidemiologists conduct research to establish the factors that lead to public health issues, the appropriate responses, interventions, and solutions.

By using research—from the field and in the lab—and statistical analysis, epidemiologists can track disease and predict its future outcomes. In the case of COVID-19, this analysis requires heavy data surveillance, collection, and interpretation. 

Due to the scale and threat of the coronavirus pandemic, testing centers, and healthcare systems are required to report all related data, providing epidemiologists with a wealth of information upon which to base their studies. With this information, epidemiologists will track data including :

Number of Incidences (how many cases over time?)

Disease Prevalence (how many cases at a specific time?)

Number of Hospitalizations

Number of Cases Resulting in Death

Epidemiological Modeling

Using this data and more, epidemiologists create models that help predict the spread of the disease in the future—including where and when the spread may occur. They may also be able to discern the most vulnerable populations likely to contract a disease and provide recommendations for intervention. See examples of our faculty's work modeling COVID data .

Contact Tracing

In an attempt to stop the spread of disease and understand where it might go next, many public health workers use contact tracing to determine the connections of an infected person. See what some of our students have been doing:  Students take the lead on the COVID-19 response .

Degrees in epidemiology

By achieving a degree in epidemiology, you are poised to work in places such as local health departments, nonprofits, government organizations, academia, the pharmaceutical industry, and more. 

With Columbia Public Health programs ranging from MPH , MS , DrPH , and  PhD , students at all levels can gain the necessary knowledge to drive public health initiatives and conduct independent epidemiological research. Our graduates go on to work in roles at companies and organizations ranging in size, scope, and mission, such as:

Data and Informatics Analysts at medical technology firms, hospitals, and universities 

Research Scientists at statewide health departments 

Fellows at the Centers for Disease Control and Prevention (CDC) 

Clinical Trial Associates at international research laboratories

Research and Evaluation Manager at nonprofit organizations

Other areas of employment among our graduates include:

Consulting firms

Health insurance companies

Marketing and strategic communications firms

Pharmaceutical and biotechnology or medical device companies

The Department of Epidemiology at Columbia University Mailman School of Public Health is committed to producing world-class science with real-world impact while training the next generation of epidemiologists to improve the health and lives of communities around the world. Apply today or explore our overview book  for more info.

Welcome to the Department of Epidemiology

We study the frequency, distribution, and determinants of disease in humans, a fundamental science of public health. In addition to pursuing groundbreaking global research initiatives, we educate and prepare future medical leaders and practitioners as part of our mission to ignite positive changes in the quality of health across the world.

We are committed to enriching the academic experience for our talented students, empowering them with the critical thinking and problem-solving skills they need to address current and future public health challenges. We offer more than seventy courses covering a broad range of topics including cancer, infectious disease, reproductive and cardiovascular epidemiology. Degree programs include Master of Public Health ( now available online ), Master of Science (one- and two-year degrees), and the Ph.D. in Population Health Sciences. Students specialize in one of twelve areas of interest and can choose from a wide variety of course offerings .

The Harvard T.H. Chan School of Public Health is in the center of the Longwood Medical Area, a Boston healthcare hub that is home to the Harvard Medical School, Brigham and Women’s Hospital, Beth Israel Deaconess Medical Center, and many other venerable institutions dedicated to improving public health worldwide. This energetic environment offers engaged students a wealth of invaluable resources as they launch their professional careers.

Our impressive faculty, led by Department Chair Professor Albert Hofman , is comprised of more than seventy-five members, including thirty-five core professors working onsite in our Boston location. Recognized for their expertise in a wide array of disciplines, our team remains at the forefront of epidemiology, actively engaged in research and regularly publishing their findings in the most respected health journals. Our researchers strive to enhance the validity and efficiency of epidemiological investigation methodologies, and expand the practical applications for these tools. The primary goals of our collaborative, multidisciplinary research are to effectively control and ultimately prevent human disease. Learn more about some outstanding accomplishments of the exceptional students in our diverse department community.

Well-grounded multidisciplinary research toward assessing the distribution and determinants of human illness with the aim of establishing reasoned preventive measures.

Methodology

Continuous efforts to improve methods for epidemiological investigation, to enhance validity and efficiency, and to expand the scope of activities in which epidemiologic methods can be usefully applied.

Preparation of future researchers and practitioners in the field of epidemiology, as well as dissemination of knowledge to health professionals and the general public. As the reach of the Harvard T.H. Chan School of Public Health is global in scope, so too is our research program. We are committed to the enhancement of quality of health not only in our own country, but internationally.

The Department of Epidemiology has a long tradition of teaching and research in the epidemiology of cancer, cardiovascular disease, and other chronic diseases, as well as in epidemiologic methodology. The department is innovative, collaborative and continuously celebrates a commitment to ignite positive changes in the world of Public Health.

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Editor-in-Chief

Enrique Schisterman

Methods in Social Epidemiology

An upcoming collection from the  American Journal of Epidemiology  for your research into methods in social epidemiology. Submissions are due May 10, 2024.

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Call for Papers: Methods in Social Epidemiology

An upcoming collection from the American Journal of Epidemiology for your research into methods in social epidemiology. Submissions are due May 10, 2024.

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Early Career Researchers: A Joint Collection

A collection of papers covering different timely topics and methodology of interest for early career researchers, some of which were written by early career researchers, from the American Journal of Epidemiology and the European Journal of Public Health .

Historical Articles and Video Interviews

Dr. Lorraine Dean, AJE Editor in Residency, interviews the authors of 4 highly cited articles to gain further insight into the thinking behind and impact of these works.

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Diversity and Inclusion in the SER: Baseline Assessment and Actionable Ideas for Improvement

The Society for Epidemiologic Research Diversity and Inclusion Committee recently undertook the task of characterizing multiple dimensions of social identity and lived experience among Society members and then assessed the relationships among these characteristics and perceptions of inclusion and participation.

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The Casual Inference podcast hosts guests from multiple fields, from epidemiology to statistics and data science. Are you already listening? 

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Mental health, Covid-19, Methods in Social Epidemiology, and more. Explore all of the published and upcoming collections from the American Journal of Epidemiology .

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The American Journal of Epidemiology is publishing timely, high-quality articles to further the scientific discourse about COVID-19 and the understanding of the pandemic.

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At the Johns Hopkins Bloomberg School of Public Health, we provide the highest quality education in epidemiology and advance the science of epidemiology through our focused research.

The Department of Epidemiology offers eight different tracks to customize our curriculum to your interests:

• Cancer Epidemiology
• Cardiovascular and Clinical Epidemiology
• Clinical Trials and Evidence Synthesis
• Environmental Epidemiology
• Epidemiology of Aging
• General Epidemiology and Methodology
• Genetic Epidemiology
• Infectious Disease Epidemiology

In addition to our extensive research, we put our findings to use through our epidemiological practice. From translating epidemiologic research findings into clinical medicine, to applying our findings to forming and evaluating public policy, the Department of Epidemiology is pioneering new ways to improve public health.

Explore Some of Our Current Projects for Each Track

Faculty research efforts extend from studies of lifestyle and host factors associated with cancer risk and progression (e.g., tobacco use, diet, and obesity), to the broad area of the molecular epidemiology of cancer to the chemoprevention of cancer. Faculty have expertise in a range of cancers and exposures and lead studies both in the U.S. and internationally. Reflecting the interdisciplinary nature of population-based cancer research, faculty in the Cancer Epidemiology Track collaborate closely with faculty within other departments of the school including Health Policy and Management , Environmental Health Sciences and International Health , faculty in other parts of Johns Hopkins University, as well as other universities. Integral to the program is a close affiliation with the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center. There is also a close collaboration with the George W. Comstock Center for Public Health Research and Prevention located in Hagerstown, Maryland that provides students and faculty with community-based research opportunities for studies of chronic disease, etiology and prevention.

Cancer Journals

• Cancer Causes & Control
• Cancer Epidemiology Biomarkers & Prevention
• Cancer Prevention Research
• Cancer Research
• International Journal of Cancer

Cancer Links

• National Cancer Institute - Division of Cancer Epidemiology
• Sidney Kimmel Comprehensive Cancer Center

Data/Sample Resources

• Atherosclerosis Risk in Communities Cohort - Cancer (ARIC-Ca)
• George W. Comstock Center for Public Health Research

Professional Organizations

• American Association for Cancer Research
• American Society of Preventive Oncology
• Minorities in Cancer Research
• Women in Cancer Research

For a complete list of research projects, visit the Welch Center for Prevention, Epidemiology and Clinical Research website .

• Aging and Cognitive Health Evaluation in Elders (ACHIEVE)
• Atherosclerosis Risk in Communities (ARIC)
• Atherosclerosis Risk in Communities - Neurocognitive Study (ARIC-NCS)
• Chronic Renal Insufficient Cohort (CRIC)
• Multi-Ethnic Study of Atherosclerosis (MESA)
• National Health and Nutrition Examination Survey (NHANES)
• Study to Understand Fall Reduction and Vitamin D in You (STURDY)

Research in aging is supported by the activities of the Center on Aging and Health (COAH) , a multidisciplinary, cross-school research center, and the Division of Geriatric Medicine and Gerontology .

• Atherosclerosis Risk In Communities (ARIC)
• Baltimore Experience Corps Study
• Baltimore Longitudinal Study on Aging (BLSA)
• Biomarkers of Cognitive Decline Among Normal Individuals Study (BIOCARD)
• Multicenter AIDS Cohort Study (MACS)
• National Health and Aging Trends Study (NHATS)
• Study of Physical Resilience in Geriatrics (SPRING)
• Study To Understand Fall Reduction and Vitamin D in You (STURDY)
• The Precursors Study
• The Multicenter AIDS Cohort Study (MACS)
• Women's Interagency HIV Study (WIHS)
• The Study of Chronic Kidney Disease in Children (CKID)
• The North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD)
• Liver Cancer, HBV and Aflatoxin
• Postmarketing Study of Tramadol
• Postmarketing Study of Opioid-Based Pain Medications
• Center for Excellence in Genomic Science
• Early Autism Risk Longitudinal Investigation (EARLI)
• Family Investigation of Nephropathy and Diabetes (FIND)
• Genetics of Glaucoma-Related Traits
• Genetics of Schizophrenia
• Host Genetics of Infectious Disease
• International Collaboration on Genetics of Cleft Lip and Palate
• Study to Explore Early Development (SEED)
• AIDS Link to Intravenous Experience (ALIVE)
• Chennai HIV, Hepatitis C and EERal Study (CHHEERS)
• H2U Consortium
• Pediatric Antiretroviral Therapy (PART) Study
• Stylish Man/Stylish Living (SMLP) Study
• Women’s Interagency HIV Study

Centers & Institutes

• Center on Aging & Health
• Wendy Klag Center for Autism & Developmental Disabilities
• Center for Clinical Trials and Evidence Synthesis
• Spatial Science for Public Health Center
• Center for Health Equity
• Center for Public Health & Human Rights
• Comstock Center for Public Health Research & Prevention
• StatEpi Coordinating Center
• Welch Center for Prevention, Epidemiology & Clinical Research
• Evidence-Based Practice Center
• Institute for Clinical & Translational Research
• Johns Hopkins Biological Repository
• Center for Drug Safety & Effectiveness
• Cochlear Center for Hearing and Public Health
• 2019 Novel Coronavirus Research Compendium
• Environmental influences on Child Health Outcomes (ECHO) Data Analysis Center (DAC)

Johns Hopkins COVID Long Study

Led by Priya Duggal, Bryan Lau, and Shruti Mehta, the Johns Hopkins COVID Long Study aims to better understand the long-term effects of COVID-19. It is open to people who have been diagnosed with COVID-19 or have experienced COVID-19 symptoms. Researchers are looking to recruit 25,000 participants.

Aging and Cognitive Health Evaluation in Elders (ACHIEVE) Study

The Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study is a research study investigating two different treatments that may promote healthy aging and cognitive health in older adults. These treatments include a successful aging education program and a hearing loss program. Study participants will be randomly selected to either receive the successful aging education or the hearing program. Drs. Frank Lin and Josef Coresh co-lead this study.

Epidemiology

View Principal Investigators in Epidemiology

When it comes to understanding the health of populations, the Intramural Research Program (IRP) is ideally structured for the long-term research that supports the field of epidemiology. Studying health patterns and outcomes in large numbers of individuals over long periods of time is no easy task, and our scientists have a number of tools available to them that specifically enable this type of research: stable funding, multi-disciplinary scientific teams, and the world’s largest hospital entirely devoted to clinical research—the NIH Clinical Center .

Epidemiology research involves not just epidemiologists, but also geneticists, biologists, sociologists, statisticians, psychologists, bioinformaticians, data scientists, and mathematicians, and of course the study participants. There are several general categories of epidemiological studies:

• Prospective cohort studies, also known as longitudinal studies , investigate the long-term health outcomes of a group of healthy people (longitudinal studies).
• Case-control studies compare individuals with a known health condition to those without it to understand why some individuals become ill and others do not.
• Cross-sectional studies compare groups at a single point in time.
• Family studies examine how disease develops in families with inherited predisposition syndromes.

IRP scientists are currently engaged in a wide range of epidemiological studies, including:

• The Baltimore Longitudinal Study of Aging (BLSA) : initiated in 1958 and conducted by the National Institute on Aging (NIA), the BLSA is America’s longest-running scientific study of human aging.
• The Sister Study : this study has enrolled more than 50,000 women with a sister who had breast cancer from across the US and Puerto Rico. Because of their shared environment, genes, and experiences, studying sisters provides a greater chance of identifying risk factors that may help us find ways to prevent breast cancer. The study is run by the National Institute of Environmental Health Sciences (NIEHS).
• The Agricultural Health Study (AHS) : this study explores a wide range of health outcomes among licensed pesticide applicators, as well as their spouses and children, to explore the health effects of exposure to pesticides and other agricultural hazards. The study is a collaboration between the National Cancer Institute (NCI), NIEHS, and the U.S. Environmental Protection Agency (EPA).
• Connect for Cancer Prevention Cohort Study : this prospective cohort study of U.S. adults, led by the NCI, is designed to investigate the causes of cancer and its outcomes, which may inform new approaches to prevention and early detection.
• Scientific Evaluation of One or Two Doses of the Bivalent or Nonavalent Prophylactic HPV Vaccines — The ESCUDDO Study : this randomized clinical trial, conducted by the NCI, compares the effectiveness of one-dose and two-dose vaccination against the Human Papilloma Virus (HPV) among 20,000 girls 12 to 16 years old residing in Costa Rica. It also tracks HPV infection among unvaccinated women ages 17 to 20.
• The Fetal Growth Studies — Singletons and Dichorionic Twins : this study, led by the Eunice Kennedy Shriver National Institute Child Health and Human Development (NICHD), was designed to establish a standard for normal fetal growth and size for gestational age in the U.S. In addition, it aims to describe fetal growth trajectories of twins compared with the standard developed for single births to determine the standard’s applicability for monitoring the growth of twins.
• Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) : this study, conducted by the National Institute on Aging (NIA), is a prospective cohort study of African American and White adults ages 30-64 living in Baltimore City. HANDLS aims to disentangle the relationships among race, socioeconomic status, and health outcomes as they relate to aging.

To learn more about those studies, visit each IRP program’s website:

• National Cancer Institute (NCI)
• National Institute on Aging (NIA)
• National Institute of Allergy and Infectious Diseases (NIAID)
• Eunice Kennedy Shriver National Institute on Child and Health and Human Development (NICHD)
• National Institute of Environmental Health Sciences (NIEHS)

IRP programs provide excellent opportunities for career training and development — from postbaccalaureate to postdoctoral fellowships. Learn more about these opportunities via the NIH Office of Intramural Training and Education .

To find out more about IRP scientists who carry out epidemiological studies, visit any of NIH’s Scientific Interest Groups focused on Epidemiology .

This page was last updated on Tuesday, October 11, 2022

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Stat 507: epidemiological research methods.

•   Overview
•   Materials
•   Assessment Plan
•   Prerequisites
•   Online Notes

The course examines the methods used in epidemiologic research, including the design of epidemiologic studies and the collection and analysis of epidemiological data. Epidemiology is the study of the distribution and determinants of human disease and health outcomes, and the application of methods to improve human health. Epidemiological studies are typically observational in nature, meaning that that the investigator has limited control over the exposure that study participants experience. Epidemiological studies are typically concerned about the health of populations, while clinical medicine is concerned with the health of individual persons.

Upon completion of the course, the student will be able to:

• Understand epidemiologic hypotheses, concepts and measures
• Describe epidemiologic study designs.
• Understand the strengths and limitations of various epidemiologic study designs.
• Design an epidemiological study.
• Identify sources of bias, confounding and effect modification in epidemiological studies.
• Analyze epidemiologic data using multivariable methods.
• Prepare and make an epidemiological presentation.
• Write an epidemiologic report.
• Write a proposal for an epidemiologic study.
• Critically read epidemiological literature.

Course Topics

Topics typically covered in STAT 507 include:

• Disease causation and epidemiological hypotheses
• case definitions
• incidence and prevalence
• rates and risk
• direct and indirect standardization
• odds, rate and risk ratios
• rate and risk differences
• population attributable risk
• cross-sectional
• case-control
• interventional
• community-based
• Bias, confounding and effect modification
• Logistic, Poisson and binomial regression
• Sample size and power in epidemiologic studies
• prevention and screening
• molecular epidemiology
• geographic variation in disease occurrence
• health disparities
•   Clinical Methods
•   Epidemiological Methods

Course Author(s)

Dr. Eugene Lengerich is the original author of these course materials. He is Professor, Department of Public Health Sciences, College of Medicine, and Director of Community Outreach and Education, Penn State Hershey Cancer Institute. The latest updates have been made by Allison Deal, a biostatistician with the UNC school of medicine.

Students will need to use software to calculate basic epidemiologic measures. This can be accomplished using a statistical software package such as SAS, R, Epiinfo, or Minitab. See the  Statistical Software page  for information regarding these applications.

• Essentials of epidemiology in public health (4th ed). (2020) by Ann Aschengrau. Published by Jones & Bartlett Learning. (ebook provided through Penn State libraries)

Recommended Texts

Readings from the literature will supplement the following texts:

• Epidemiology: Study design and data analysis . (2005) by Mark Woodward. Published by Chapman and Hall/CRC.

Last updated: FA23

Assessment Plan

• Activities - 25%
• Literature Critiques - 15%
• Surveillance Project - 25%
• Study Proposal Project - 35%

Prerequisites

3 credits in statistics, STAT 250 or equivalent.

Established in 1968 to foster epidemiologic research, the Society for Epidemiologic Research is the oldest and largest general epidemiology society in North America.

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Serwebinars, serpresents: “a call for descriptive epidemiology”.

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Thoughts on Meaningful and Interpretable Data Science for Environmental Epidemiology

SER offers something for everyone, irrespective of your level of training.

The mission of the society for epidemiologic research is to keep epidemiologists at the vanguard of scientific developments., your membership with ser includes the american journal of epidemiology and epidemiologic reviews, m-estimation, mixed and multilevel modeling: out of the darkness into the light, quasi-experimental methods based on the timing of the intervention, sampling hard-to-reach populations, healthy worker survivor bias, ser calendar, serpresents - novel approaches to cancer epidemiology: molecular epidemiology that integrates tumor heterogeneity strengthens causal inference.

Join Tomotaka Ugai, Hwa-young Lee, Cheng Peng, Minkyo Song, Konrad H. Stopsack, and Kaoko Sasamoto in their discussion of Molecular Epidemiology that IntegratesTumor Heterogeneity Strengthens Causal Inference.

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School of Medicine Department of Medical Informatics and Clinical Epidemiology

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Department of Medical Informatics and Clinical Epidemiology

Clinical epidemiology research.

Clinical epidemiology is the study of the patterns, causes, and effects of health and disease in patient populations and the relationships between exposures or treatments and health outcomes. Areas of research include disease screening and prevention, systematic review methodology, comparative effectiveness research, developing evidence-based practice and policy guidelines, implementation of practices and guidelines in health systems, development of patient-centered registries and data marts within health information systems, creating and testing patient decision aids, and using patient data for quality improvement and research projects.

Among the areas of research expertise include:

• Evidence-based medicine
• Systematic reviews and meta-analysis
• Screening and prevention
• Clinical practice guidelines

Some grant-funded projects include:

Pacific Northwest Evidence-based Practice Center Roger Chou, Marian McDonagh The Pacific Northwest Evidence-based Practice Center (EPC) conducts systematic reviews of healthcare topics for federal and state agencies and private foundations. These reviews report the evidence from clinical research studies and the quality of that evidence for use by policymakers in decisions on guidelines and coverage issues.

The Evidence-based Practice Center in the OHSU School of Medicine, Department of Medical Informatics and Clinical Epidemiology celebrated its 25th anniversary with a reception Oct. 7 2022 at Richard Jones Hall.  The reception was attended by School of Medicine Interim Dean David Jacoby, M.D., and OHSU Provost Marie Chisholm-Burns, Pharm.D., Ph.D., M.P.H., M.B.A. Here are the slides from the event .

Nationally recognized as one of the most successful centers of its kind, the OHSU Evidence-based Practice Center is the place where exhaustive reviews of literature and research are conducted to craft the gold standard for patient care and health policy in areas ranging from chronic pain to brain trauma. More on the Center here.  To view the presentations from the event please click here . Funder: Agency for Healthcare Research & Quality

A Cluster-Randomized Trial Comparing Team-Based versus Primary Care Clinician-Focused Advance Care Planning in Practice-Based Research Networks Annette Totten A contract awarded to the Oregon Rural Practice-based Research Network (ORPRN) by the Patient-Centered Outcomes Research Institute (PCORI).

Data Coordinating Center for Vitamin C and Smoking in Pregnancy Project Cindy Morris The beneficial infant outcomes of maternal vitamin C supplementation (500 mg/day) in pregnant smokers is supported by a robust pre-trial evidence in animal models and convincing human pilot data. This evidence served as the basis for the project's current multi-center double blind randomized trial “Vitamin C to Decrease Effects of Smoking in Pregnancy on Infant Lung Function.”  

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• Clinical Research Explained

Epidemiology

• 29. March 2024

Concepts in Epidemiology

Incidence and prevalence, risk factors and outcomes, methodologies in epidemiology, observational studies, experimental studies, statistical analysis, applications of epidemiology in clinical research, identifying risk factors, testing interventions, monitoring health services, challenges in epidemiological research, selection bias, information bias, confounding.

Epidemiology is the cornerstone of public health, and informs policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. In the field of clinical research, epidemiology plays a critical role in understanding the distribution, causes, and effects of health and disease conditions in defined populations.

This glossary article aims to provide a comprehensive understanding of epidemiology in the context of clinical research. It will delve into the key concepts, methodologies, and applications of epidemiology, and how it intersects with various aspects of clinical research. The goal is to equip readers with a solid foundation of knowledge on this subject, which is integral to the field of health sciences.

Epidemiology is built on several key concepts that help researchers understand and investigate patterns, causes, and effects of health and disease conditions in specific populations. These concepts include incidence, prevalence, risk factors, and outcomes.

Incidence refers to the number of new cases of a disease or condition in a specific population during a specific time period. Prevalence, on the other hand, refers to the total number of cases, both new and existing, in a population at a given time. Risk factors are characteristics that increase the likelihood of developing a disease or health disorder. Outcomes refer to the effects that a disease or condition has on a person’s life.

Incidence and prevalence are two fundamental measures in epidemiology. They provide insights into the burden of disease in a population. Incidence is particularly useful for studying the causes of disease, as it reflects the number of new cases. Prevalence, on the other hand, provides a snapshot of the total burden of a disease at a particular time, and is useful for planning healthcare services.

It’s important to note that incidence and prevalence are related. The prevalence of a disease is influenced by both its incidence and the average duration of the disease. If the incidence or duration increases, the prevalence will also increase, and vice versa.

Risk factors are characteristics that increase an individual’s chances of developing a disease or health disorder. They can be behaviors, such as smoking or physical inactivity, biological factors, such as age or genetics, or environmental exposures, such as air pollution or occupational hazards. Identifying risk factors is a key step in preventing disease and promoting health.

Outcomes in epidemiology refer to the effects that a disease or condition has on a person’s life. They can be measured in various ways, including mortality (death), morbidity (illness), disability, quality of life, and financial cost. Understanding outcomes is crucial for evaluating the effectiveness of interventions and for guiding policy and practice.

Epidemiology employs a range of methodologies to investigate the distribution and determinants of health and disease. These include observational studies, experimental studies, and statistical analysis.

Observational studies involve observing subjects and measuring their outcomes without influencing them. They can be descriptive, where the aim is to describe the distribution of a disease, or analytical, where the aim is to identify associations between exposures and outcomes. Experimental studies, on the other hand, involve the researcher intervening in some way to see the effect on the outcomes. Statistical analysis is used to interpret the data and draw conclusions.

Observational studies are a cornerstone of epidemiology. They involve observing subjects in their natural settings and measuring their outcomes. There are several types of observational studies, including cohort studies, case-control studies, and cross-sectional studies.

Cohort studies involve following a group of people over time to see who develops the disease of interest. They are particularly useful for studying rare exposures. Case-control studies, on the other hand, start with people who have the disease (cases) and people who do not have the disease (controls), and look back in time to see what exposures they had. They are useful for studying rare diseases. Cross-sectional studies measure the exposure and disease at the same time, and are useful for studying the prevalence of a disease.

Experimental studies in epidemiology involve the researcher intervening in some way to see the effect on the outcomes. The most common type of experimental study in epidemiology is the randomized controlled trial (RCT). In an RCT, subjects are randomly assigned to either the treatment group or the control group, and the outcomes are compared between the two groups.

RCTs are considered the gold standard for determining the effectiveness of interventions because the random assignment helps to eliminate confounding factors. However, they are often expensive and time-consuming to conduct, and in some cases, it may not be ethical or feasible to randomly assign subjects to exposures.

Statistical analysis is a key component of epidemiological research. It involves using statistical methods to interpret the data and draw conclusions. There are many different statistical techniques that can be used, depending on the research question and the type of data.

Some common statistical methods used in epidemiology include regression analysis, which is used to model the relationship between an outcome and one or more exposures; survival analysis, which is used to analyze time-to-event data; and meta-analysis, which is used to combine the results of multiple studies.

Epidemiology has many applications in clinical research, from identifying risk factors and testing interventions, to monitoring the effectiveness of healthcare services and informing policy decisions. It provides the scientific basis for evidence-based medicine and helps to ensure that healthcare resources are used effectively and efficiently.

One of the key applications of epidemiology in clinical research is in the design and conduct of clinical trials. Epidemiological methods are used to determine the sample size, select the subjects, measure the exposures and outcomes, and analyze the data. The results of clinical trials can then be used to inform clinical practice and policy decisions.

One of the primary applications of epidemiology in clinical research is in identifying risk factors for disease. By studying the distribution and determinants of disease in populations, epidemiologists can identify factors that increase the risk of developing a disease. These risk factors can then be targeted in prevention and intervention strategies.

For example, epidemiological studies have identified smoking as a risk factor for lung cancer, high blood pressure as a risk factor for stroke, and physical inactivity as a risk factor for heart disease. These findings have led to public health campaigns to reduce smoking, control blood pressure, and promote physical activity, which have in turn reduced the burden of these diseases.

Epidemiology also plays a crucial role in testing interventions to prevent or treat disease. Randomized controlled trials, which are a type of experimental study, are often used to test the effectiveness of new drugs, vaccines, or behavioral interventions. The results of these trials can then be used to inform clinical practice and public health policy.

For example, randomized controlled trials have shown that antiretroviral therapy is effective in treating HIV, that the HPV vaccine is effective in preventing cervical cancer, and that cognitive-behavioral therapy is effective in treating depression. These findings have led to changes in clinical practice and have had a major impact on public health.

Epidemiology is also used to monitor the effectiveness and efficiency of health services. By measuring the incidence and prevalence of diseases, and the outcomes of patients, epidemiologists can assess the impact of health services and identify areas for improvement.

For example, epidemiological studies have shown that access to primary care is associated with better health outcomes, that screening programs can reduce the mortality of certain cancers, and that hospital readmission rates can be used as a measure of healthcare quality. These findings have informed the planning and evaluation of health services, and have led to improvements in healthcare delivery.

While epidemiology is a powerful tool in clinical research, it also faces several challenges. These include issues related to study design, data collection, and interpretation of results.

Study design issues include selection bias, where the selection of subjects into the study is related to both the exposure and the outcome; information bias, where the measurement of the exposure or the outcome is inaccurate; and confounding, where an observed association is actually due to a third factor that is associated with both the exposure and the outcome.

Selection bias occurs when the selection of subjects into the study is related to both the exposure and the outcome. This can lead to an overestimate or underestimate of the true association between the exposure and the outcome.

For example, if a study of the association between smoking and lung cancer only includes hospital patients, it may overestimate the association because hospital patients are more likely to be smokers and to have lung cancer than the general population. To avoid selection bias, it’s important to select the study subjects in a way that is independent of their exposure and outcome status.

Information bias occurs when the measurement of the exposure or the outcome is inaccurate. This can lead to an overestimate or underestimate of the true association between the exposure and the outcome.

For example, if a study of the association between diet and heart disease relies on self-reported dietary intake, it may be subject to recall bias, where subjects do not accurately remember what they ate. To avoid information bias, it’s important to use reliable and valid measures of the exposure and the outcome.

Confounding occurs when an observed association between an exposure and an outcome is actually due to a third factor that is associated with both the exposure and the outcome. This can lead to an overestimate or underestimate of the true association between the exposure and the outcome.

For example, if a study of the association between exercise and heart disease does not control for age, it may be confounded by age, because older people are less likely to exercise and more likely to have heart disease. To control for confounding, it’s important to measure potential confounders and to adjust for them in the analysis.

Epidemiology is a key discipline in clinical research, providing the tools and methodologies to understand the distribution and determinants of health and disease in populations. It informs clinical practice and public health policy, and helps to ensure that healthcare resources are used effectively and efficiently.

While epidemiology faces several challenges, including issues related to study design, data collection, and interpretation of results, it continues to evolve and adapt to these challenges. With the advent of new technologies and data sources, the field of epidemiology is poised to make even greater contributions to clinical research in the future.

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• Frontiers in Public Health
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Women in Science: Infectious Diseases: Epidemiology and Prevention 2023

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About this Research Topic

The proportion of women and men in science, technology, engineering, and mathematics (STEM) at undergraduate levels is relatively equal. However, there is a lack of representation of women in senior positions in Public Health. According to the UNESCO Institute for Statistics (UIS) data in 2016, less than 30% ...

Keywords : Women, STEM, diversity, UNESCO, Public Health, Infectious Diseases

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Oak Ridge Institute for Science and Education

Cdc grasp gis geospatial epidemiology and applied research fellowship.

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Description

*Applications will be reviewed on a rolling-basis.

CDC Office and Location: A research opportunity is available in the Centers for Disease Control and Prevention (CDC) located in Atlanta, Georgia. Selected candidates must either live within a 50 mile radius of an approved CDC duty location or be able to relocate before the start of the appointment.

The Centers for Disease Control and Prevention (CDC) is one of the major operation components of the Department of Health and Human Services. CDC works to protect America from health, safety and security threats, both foreign and in the U.S. Whether diseases start at home or abroad, are chronic or acute, curable or preventable, human error or deliberate attack, CDC fights disease and supports communities and citizens to do the same.

For nearly 30 years, GRASP has led the application of geography in public health to prevent disease, prolong life, and promote health. GRASP works across the Centers for Disease Control and Prevention (CDC), the Agency for Toxic Substances and Disease Registry (ATSDR), and the public health community to examine patterns associated with environmental health, public health emergencies, infectious and chronic disease, and injury.

Research Project: The Fellow will:

• Compile information on SVI within U.S. territories
• Determine data availability for U.S. territories or how to best approximate SVI
• Collaborate with the team to develop tools and resources for the SVI to support U.S. territories

Possible Project Areas:

• Participate in outreach and engagement efforts to support the development and expansion of SVI
• Create materials, including SVI fact sheets and data snapshots, toolkits for health departments, video tutorials, and other community resources
• Support SVI projects in environmental, infectious disease, chronic illness, injury, and disaster epidemiology
• Assist with data and technology to support the update and expansion of SVI information to the public

Learning Objectives: As a result of this training, the participant will improve their skills in research and project development, GIS and data visualization, and communicating public health results and information to the public.

Mentor(s): The mentor for this opportunity is Shannon Graham ( [email protected] ). If you have questions about the nature of the research please contact the mentor(s).

Anticipated Appointment Start Date: 2024. Start date is flexible and will depend on a variety of factors.

Appointment Length: The appointment will initially be for five years, but may be renewed upon recommendation of CDC and is contingent on the availability of funds.

Level of Participation: The appointment is full time.

Participant Stipend: Stipend rates may vary based on numerous factors, including opportunity, location, education, and experience. If you are interviewed, you can inquire about the exact stipend rate at that time and if selected, your appointment offer will include the monthly stipend rate.

Citizenship Requirements: This opportunity is available to U.S. citizens, Lawful Permanent Residents (LPR), and foreign nationals. Non-U.S. citizen applicants should refer to the Guidelines for Non-U.S. Citizens Details page of the program website for information about the valid immigration statuses that are acceptable for program participation.

ORISE Information: This program, administered by ORAU through its contract with the U.S. Department of Energy (DOE) to manage the Oak Ridge Institute for Science and Education (ORISE), was established through an interagency agreement between DOE and CDC. Participants do not become employees of CDC, DOE or the program administrator, and there are no employment-related benefits. Proof of health insurance is required for participation in this program. Health insurance can be obtained through ORISE.

The successful applicant(s) will be required to comply with Environmental, Safety and Health (ES&H) requirements of the hosting facility, including but not limited to, COVID-19 requirements (e.g. facial covering, physical distancing, testing, vaccination).

Questions: Please visit our Program Website . After reading, if you have additional questions about the application process please email [email protected] and include the reference code for this opportunity.

Qualifications

The qualified candidate should be currently pursuing or have received a bachelor’s, master’s, or doctoral degree in the one of the relevant fields. Degree must have been received within the past five years or anticipated to be received by 5/31/2025.

Preferred skills:

• Degree or coursework in public health, communications, social sciences, or geography is preferred.
• Experience or competency with one or more of the following: U.S. Census data and American Community Survey, WPCMS, ArcGIS Online, R, Tableau, PowerBI, SQL.
• Professional or academic experience with one or more of the following: social vulnerability, communications, data visualization, health equity, public health.

Eligibility Requirements

• Degree: Bachelor’s Degree, Master’s Degree, or Doctoral Degree received within the last 60 months or anticipated to be received by 5/31/2025 12:00:00 AM.

Researcher Senior - Safety and Epidemiology Research

Job Posting for Researcher Senior - Safety and Epidemiology Research at Elevance Health

Description.

Location: This position will work a hybrid model (remote and in office one day per week). Ideal candidates will live within 50 miles of one of our Pulse Point locations in Wilmington, DE, Newton, MA, Indianapolis, IN, Chicago, IL, Cary, NC, Richmond, VA, Roanoke, VA, Norfolk, VA, Mason, OH, Portland, ME, St. Louis, MO, Wallingford, CT or Louisville, KY.

The Researcher Senior - Safety and Epidemiology Research is responsible for prospective and retrospective epidemiologic research activities for Carelon Research clients or Public Policy Institute (PPI).

How you will make an impact:

Lead and support the design and execution of pharmacoepidemiology research, including post-authorization safety, risk mitigation, and active monitoring studies.

Provide epidemiology subject matter expertise and lead or support research activities related to scientific study design, application of appropriate statistical methods, interpretation of results, reporting, and communication of results.

Lead and contribute to the development of protocols, statistical analysis plans, reports, and publications.

Lead or support the development of detailed specifications for study databases and analysis files, consistency checks, tables, and figures and communicates requirements to the programming group.

Conduct review of administrative claims data and statistical output to ensure the superior quality of research activities and client deliverables.

Lead or support initiatives that leverage and enhance the research environment.

Publish research findings and present at professional scientific meetings.

Present the company’s epidemiology expertise to prospective clients and support business development activities, including proposal development.

Accountable to the final quality and accuracy of these study deliverables and presentation of such and facilitates collaboration among project team members towards their development.

Minimum Requirements:

Requires a MS, MPH or PharmD in epidemiology or health sciences or related field; minimum 3 years of experience in health service research, epidemiology, biostatistics, or a related field; or any combination of education and experience which would provide an equivalent background.

Preferred Skills, Capabilities, and Experiences:

Expert knowledge of epidemiology study design and statistical methodology strongly preferred.

Experience leading research teams in the design and execution of pharmacoepidemiology studies strongly preferred.

Experience with healthcare claims data and knowledge of advanced statistical methods used in the evaluation of healthcare claims data strongly preferred.

Experience with consulting for the life sciences industry strongly preferred.

Proficiency in SAS statistical software strongly preferred.

Proficiency in R statistical software strongly preferred.

Proficiency using the Panalgo Instant Health Data (IHD) tool strongly preferred.

Innovative in conducting statistical analysis strongly preferred.

Experience managing and prioritizing multiple projects to ensure their quality and on-time delivery strongly preferred.

Ph.D. or MD strongly preferred.

Clinical or therapeutic area knowledge, familiarity with clinical practice guidelines, and/or understanding of the U.S. health care system strongly preferred.

Strong attention to detail preferred.

Adaptable to changing priorities preferred.

Please be advised that Elevance Health only accepts resumes for compensation from agencies that have a signed agreement with Elevance Health. Any unsolicited resumes, including those submitted to hiring managers, are deemed to be the property of Elevance Health.

Elevance Health is a health company dedicated to improving lives and communities – and making healthcare simpler. We are a Fortune 25 company with a longstanding history in the healthcare industry, looking for leaders at all levels of the organization who are passionate about making an impact on our members and the communities we serve.

How We Work

At Elevance Health, we are creating a culture that is designed to advance our strategy but will also lead to personal and professional growth for our associates. Our values and behaviors are the root of our culture. They are how we achieve our strategy, power our business outcomes and drive our shared success - for our consumers, our associates, our communities and our business.

We offer a range of market-competitive total rewards that include merit increases, paid holidays, Paid Time Off, and incentive bonus programs (unless covered by a collective bargaining agreement), medical, dental, vision, short and long term disability benefits, 401(k) match, stock purchase plan, life insurance, wellness programs and financial education resources, to name a few.

Elevance Health operates in a Hybrid Workforce Strategy. Unless specified as primarily virtual by the hiring manager, associates are required to work at an Elevance Health location at least once per week, and potentially several times per week. Specific requirements and expectations for time onsite will be discussed as part of the hiring process. Candidates must reside within 50 miles or 1-hour commute each way of a relevant Elevance Health location.

The health of our associates and communities is a top priority for Elevance Health. We require all new candidates in certain patient/member-facing roles to become vaccinated against COVID-19. If you are not vaccinated, your offer will be rescinded unless you provide an acceptable explanation. Elevance Health will also follow all relevant federal, state and local laws.

Elevance Health is an Equal Employment Opportunity employer and all qualified applicants will receive consideration for employment without regard to age, citizenship status, color, creed, disability, ethnicity, genetic information, gender (including gender identity and gender expression), marital status, national origin, race, religion, sex, sexual orientation, veteran status or any other status or condition protected by applicable federal, state, or local laws. Applicants who require accommodation to participate in the job application process may contact [email protected] for assistance.

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Research Assistant II - Epidemiology, Human Genetics, and Environmental Sciences

Epidemiology, Human Genetics, and Environmental Sciences - UTHealth Houston Careers , Houston, TX

Senior Public Health Researcher

American Institutes for Research , Washington, DC

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Moffitt Cancer Center

Applied research scientist_cancer epidemiology.

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At Moffitt Cancer Center, we come face-to-face with cancer every day, but we also see courage. And it inspires us to be the safest and best place for cancer care – to bring greater hope to every patient we serve. It’s why we’ve been continually named One of the Top Places to Work in the Tampa Bay Area. As the only National Cancer Institute-designated Comprehensive Cancer Center based in Florida, Moffitt employs some of the best and brightest minds from around the world. Moffitt is the leading cancer hospital in both Florida and the Southeast and has been nationally ranked by U.S. News & World Report since 1999. Because working at Moffitt is both a career and a mission: to contribute to the prevention and cure of cancer. Join a dedicated, diverse and inclusive team of over 7,000 to be a part of the Courageous future we envision.

Applied Research Scientist

The Applied Research Scientist position will support the research and research team activities of Dr. Anna Giuliano , an epidemiologist with ongoing investigations to understand infection-related cancers, particularly to develop improved methods for their prevention through screening and improved treatments. Dr. Giuliano leads multiple domestic and multinational studies, including development of early detection cancer biomarkers, clinical trials for the prevention of HPV-related cancers among people living with HIV in Latin America and the Caribbean, and research of understudied virally-associated cancers among men and women living with HIV in sub-Saharan Africa.

This position is comparable to a staff scientist role: an essential contributor to analysis, writing, and grant preparation for ongoing and future research projects under the general direction of Dr. Giuliano. This position will have ample opportunities for authorship and other documentable career-enhancing activities.

Position Highlights:

• Writes and prepares manuscripts for peer-reviewed publication of a variety of research studies
• Independently works with biostatisticians to complete statistical analyses
• Generates scientific sections of grant applications with appropriate guidance
• Develops and initiates protocols for and high-level coordination of multiple studies
• Potential to network in large international research consortia

The Ideal Candidate:

• PhD in epidemiology, with a focus in infectious disease and/or cancer epidemiology, or a closely aligned quantitative field
• Has research experience in the academic and/or clinical setting, preferably in oncology
• Strong writing skills and enthusiasm for writing as demonstrated by first author publications
• Statistical programming experience, including demonstrated proficiency in SAS and R
• Experience collaborating in a multidisciplinary environment
• A critical, independent, and creative thinker
• A professional, personable, and organized individual
• Excellent oral and written communication skills. Grant writing experience is highly desired

Responsibilities:

• Under appropriate direction and guidance, performs research and related support activities including, (a) development, implementation, and management of research projects; (b) preparation of drafts of regulatory protocols and reports, manuscripts, and grants and (c) presentation of research at scientific meetings
• Interacts closely with Investigators and their collaborators in the consortium setting.
• Maintains membership and regularly attends appropriate professional associations, conferences, workshops, lectures, and seminars as supported by the overseeing Investigators.

Credentials and Qualifications:

• Minimum of an M.D. or Ph.D. in a discipline relevant to epidemiology or related field is required
• 2 years post-doctoral experience is preferred
• Experience working on research related to HPV and/or HIV is preferred

Equal Employment Opportunity

Moffitt Cancer Center is an Equal Opportunity/Affirmative Action Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, or protected veteran or disabled status. We seek candidates whose skills, and personal and professional experience, have prepared them to contribute to our commitment to diversity and excellence.

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Clinical Research Coordinator A/B - Center for Clinical Epidemiology and Biostatistics

• Screening, recruiting, and consenting patients according to protocol
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• Assisting with regulatory submissions
• Communicating with study team members
• Organizing and maintaining all documentation
• Collecting and processing study specimens
• Participating in reoccurring study team meetings
• Showing vigilance in patient safety, protocol compliance, and data integrity
• Adhering to all University of Pennsylvania and GCP guidelines
• Health, Life, and Flexible Spending Accounts : Penn offers comprehensive medical, prescription, behavioral health, dental, vision, and life insurance benefits to protect you and your family's health and welfare. You can also use flexible spending accounts to pay for eligible health care and dependent care expenses with pre-tax dollars.
• Tuition : Take advantage of Penn's exceptional tuition benefits. You, your spouse, and your dependent children can get tuition assistance here at Penn. Your dependent children are also eligible for tuition assistance at other institutions.
• Retirement: Penn offers generous retirement plans to help you save for your future. Penn's Basic, Matching, and Supplemental retirement plans allow you to save for retirement on a pre-tax or Roth basis. Choose from a wide variety of investment options through TIAA and Vanguard.
• Time Away from Work: Penn provides you with a substantial amount of time away from work during the course of the year. This allows you to relax, take vacations, attend to personal affairs, recover from illness or injury, spend time with family—whatever your personal needs may be.
• Long-Term Care Insurance: In partnership with Genworth Financial, Penn offers faculty and staff (and your eligible family members) long-term care insurance to help you cover some of the costs of long-term care services received at home, in the community or in a nursing facility. If you apply when you're newly hired, you won't have to provide proof of good health or be subject to underwriting requirements. Eligible family members must always provide proof of good health and are subject to underwriting.
• Wellness and Work-life Resources : Penn is committed to supporting our faculty and staff as they balance the competing demands of work and personal life. That's why we offer a wide variety of programs and resources to help you care for your health, your family, and your work-life balance.
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• Discounts and Special Services : From arts and entertainment to transportation and mortgages, you'll find great deals for University faculty and staff. Not only do Penn arts and cultural centers and museums offer free and discounted admission and memberships to faculty and staff. You can also enjoy substantial savings on other goods and services such as new cars from Ford and General Motors, cellular phone service plans, movie tickets, and admission to theme parks.
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Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996.

Medical Microbiology. 4th edition.

Chapter 9 epidemiology.

Philip S. Brachman .

• General Concepts

Definitions

Epidemiology is the study of the determinants, occurrence, and distribution of health and disease in a defined population. Infection is the replication of organisms in host tissue, which may cause disease. A carrier is an individual with no overt disease who harbors infectious organisms. Dissemination is the spread of the organism in the environment.

• Chain of Infection

There are three major links in disease occurrence: the etiologic agent, the method of transmission (by contact, by a common vehicle, or via air or a vector), and the host.

• Epidemiologic Methods

Epidemiologic studies may be (1) descriptive, organizing data by time, place, and person; (2) analytic, incorporating a case-control or cohort study; or (3) experimental. Epidemiology utilizes an organized approach to problem solving by: (1) confirming the existence of an epidemic and verifying the diagnosis; (2) developing a case definition and collating data on cases; (3) analyzing data by time, place, and person; (4) developing a hypothesis; (5) conducting further studies if necessary; (6) developing and implementing control and prevention measures; (7) preparing and distributing a public report; and (8) evaluating control and preventive measures.

• Introduction

This chapter reviews the general concepts of epidemiology, which is the study of the determinants, occurrence, distribution, and control of health and disease in a defined population. Epidemiology is a descriptive science and includes the determination of rates, that is, the quantification of disease occurrence within a specific population. The most commonly studied rate is the attack rate: the number of cases of the disease divided by the population among whom the cases have occurred. Epidemiology can accurately describe a disease and many factors concerning its occurrence before its cause is identified. For example, Snow described many aspects of the epidemiology of cholera in the late 1840s, fully 30 years before Koch described the bacillus and Semmelweis described puerperal fever in detail in 1861 and recommended appropriate control and prevention measures a number of years before the streptococcal agent was fully described. One goal of epidemiologic studies is to define the parameters of a disease, including risk factors, in order to develop the most effective measures for control. This chapter includes a discussion of the chain of infection, the three main epidemiologic methods, and how to investigate an epidemic ( Table 9-1 ).

Epidemiologic Methods and Investigation.

Proper interpretation of disease-specific epidemiologic data requires information concerning past as well as present occurrence of the disease. An increase in the number of reported cases of a disease that is normal and expected, representing a seasonal pattern of change in host susceptibility, does not constitute an epidemic. Therefore, the regular collection, collation, analysis, and reporting of data concerning the occurrence of a disease is important to properly interpret short-term changes in occurrence.

A sensitive and specific surveillance program is important for the proper interpretation of disease occurrence data. Almost every country has a national disease surveillance program that regularly collects data on selected diseases. The quality of these programs varies, but, generally, useful data are collected that are important in developing control and prevention measures. There is an international agreement that the occurrence of three diseases—cholera, plague, and yellow fever—will be reported to the World Health Organization in Geneva, Switzerland. In the United States, the Centers for Disease Control and Prevention (CDC), U.S. Public Health Service, and the state health officers of all 50 states have agreed to report the occurrence of 51 diseases weekly and of another 10 diseases annually from the states to the CDC. Many states have regulations or laws that mandate reporting of these diseases and often of other diseases of specific interest to the state health department.

The methods of case reporting vary within each state. Passive reporting is one of the main methods. In such a case, physicians or personnel in clinics or hospitals report occurrences of relevant diseases by telephone, postcard, or a reporting form, usually at weekly intervals. In some instances, the report may be initiated by the public health or clinical laboratory where the etiologic agent is identified. Some diseases, such as human rabies, must be reported by telephone as soon as diagnosed. In an active surveillance program, the health authority regularly initiates the request for reporting. The local health department may call all or some health care providers at regular intervals to inquire about the occurrence of a disease or diseases. The active system may be used during an epidemic or if accurate data concerning all cases of a disease are desired.

The health care provider usually makes the initial passive report to a local authority, such as a city or county health department. This unit collates its data and sends a report to the next highest health department level, usually the state health department.

The number of cases of each reportable disease are presented weekly, via computer linkage, by the state health department to the CDC. Data are analyzed at each level to develop needed information to assist public health authorities in disease control and prevention. For some diseases, such as hepatitis, the CDC requests preparation of a separate case reporting form containing more specific details.

In addition, the CDC prepares and distributes routine reports summarizing and interpreting the analyses and providing information on epidemics and other appropriate public health matters. Most states and some county health departments also prepare and distribute their own surveillance reports. The CDC publishes Morbidity and Mortality Weekly Report, which is available for a small fee from the Massachusetts Medical Society. The CDC also prepares more detailed surveillance reports for specific diseases, as well as an annual summary report, all of which can also be obtained through the Massachusetts Medical Society.

Infection is the replication of organisms in the tissue of a host; when defined in terms of infection, disease is overt clinical manifestation. In an inapparent (subclinical) infection, an immune response can occur without overt clinical disease. A carrier (colonized individual) is a person in whom organisms are present and may be multiplying, but who shows no clinical response to their presence. The carrier state may be permanent, with the organism always present; intermittent, with the organism present for various periods; or temporary, with carriage for only a brief period. Dissemination is the movement of an infectious agent from a source directly into the environment; when infection results from dissemination, the source, if an individual, is referred to as a dangerous disseminator.

Infectiousness is the transmission of organisms from a source, or reservoir (see below), to a susceptible individual. A human may be infective during the preclinical, clinical, postclinical, or recovery phase of an illness. The incubation period is the interval in the preclinical period between the time at which the causative agent first infects the host and the onset of clinical symptoms; during this time the agent is replicating. Transmission is most likely during the incubation period for some diseases such as measles; in other diseases such as shigellosis, transmission occurs during the clinical period. The individual may be infective during the convalescent phase, as in diphtheria, or may become an asymptomatic carrier and remain infective for a prolonged period, as do approximately 5% of persons with typhoid fever.

The spectrum of occurrence of disease in a defined population includes sporadic (occasional occurrence); endemic (regular, continuing occurrence); epidemic (significantly increased occurrence); and pandemic (epidemic occurrence in multiple countries).

The chain of infection includes the three factors that lead to infection: the etiologic agent, the method of transmission, and the host ( Fig. 9-1 ). These links should be characterized before control and prevention measures are proposed. Environmental factors that may influence disease occurrence must be evaluated.

Summary of important aspects involved in the chain of any infection.

Etiologic Agent

The etiologic agent may be any microorganism that can cause infection. The pathogenicity of an agent is its ability to cause disease; pathogenicity is further characterized by describing the organism's virulence and invasiveness. Virulence refers to the severity of infection, which can be expressed by describing the morbidity (incidence of disease) and mortality (death rate) of the infection. An example of a highly virulent organism is Yersinia pestis, the agent of plague, which almost always causes severe disease in the susceptible host.

The invasiveness of an organism refers to its ability to invade tissue. Vibrio cholerae organisms are noninvasive, causing symptoms by releasing into the intestinal canal an exotoxin that acts on the tissues. In contrast, Shigella organisms in the intestinal canal are invasive and migrate into the tissue.

No microorganism is assuredly avirulent. An organism may have very low virulence, but if the host is highly susceptible, as when therapeutically immunosuppressed, infection with that organism may cause disease. For example, the poliomyelitis virus used in oral polio vaccine is highly attenuated and thus has low virulence, but in some highly susceptible individuals it may cause paralytic disease.

Other factors should be considered in describing the agent. The infecting dose (the number of organisms necessary to cause disease) varies according to the organism, method of transmission, site of entrance of the organism into the host, host defenses, and host species. Another agent factor is specificity; some agents (for example, Salmonella typhimurium) can infect a broad range of hosts; others have a narrow range of hosts. Styphi, for example, infects only humans. Other agent factors include antigenic composition, which can vary within a species (as in influenza virus or Streptococcus species); antibiotic sensitivity; resistance transfer plasmids (see Ch. 5 ); and enzyme production.

The reservoir of an organism is the site where it resides, metabolizes, and multiplies. The source of the organism is the site from which it is transmitted to a susceptible host, either directly or indirectly through an intermediary object. The reservoir and source can be different; for example, the reservoir for S typhi could be the gallbladder of an infected individual, but the source for transmission might be food contaminated by the carrier. The reservoir and source can also be the same, as in an individual who is a permanent nasal carrier of S aureus and who disseminates organisms from this site. The distinction can be important when considering where to apply control measures.

Method of Transmission

The method of transmission is the means by which the agent goes from the source to the host. The four major methods of transmission are by contact, by common vehicle, by air or via a vector.

In contact transmission the agent is spread directly, indirectly, or by airborne droplets. Direct contact transmission takes place when organisms are transmitted directly from the source to the susceptible host without involving an intermediate object; this is also referred to as person-to-person transmission. An example is the transmission of hepatitis A virus from one individual to another by hand contact. Indirect transmission occurs when the organisms are transmitted from a source, either animate or inanimate, to a host by means of an inanimate object. An example is transmission of Pseudomonas organisms from one individual to another by means of a shaving brush. Droplet spread refers to organisms that travel through the air very short distances, that is, less than 3 feet from a source to a host. Therefore, the organisms are not airborne in the true sense. An example of a disease that may be spread by droplets is measles.

Common-vehicle transmission refers to agents transmitted by a common inanimate vehicle, with multiple cases resulting from such exposure. This category includes diseases in which food or water as well as drugs and parenteral fluids are the vehicles of infection. Examples include food-borne salmonellosis, waterborne shigellosis, and bacteremia resulting from use of intravenous fluids contaminated with a gram-negative organism.

The third method of transmission, airborne transmission, refers to infection spread by droplet nuclei or dust. To be truly airborne, the particles should travel more than 3 feet through the air from the source to the host. Droplet nuclei are the residue from the evaporation of fluid from droplets, are light enough to be transmitted more than 3 feet from the source, and may remain airborne for prolonged periods. Tuberculosis is primarily an airborne disease; the source may be a coughing patient who creates aerosols of droplet nuclei that contain tubercle bacilli. Infectious agents may be contained in dust particles, which may become resuspended and transmitted to hosts. An example occurred in an outbreak of salmonellosis in a newborn nursery in which Salmonella -contaminated dust in a vacuum cleaner bag was resuspended when the equipment was used repeatedly, resulting in infections among the newborns.

The fourth method of transmission is vector borne transmission, in which arthropods are the vectors. Vector transmission may be external or internal. External, or mechanical, transmission occurs when organisms are carried mechanically on the vector (for example, Salmonella organisms that contaminate the legs of flies). Internal transmission occurs when the organisms are carried within the vector. If the pathogen is not changed by its carriage within the vector, the carriage is called harborage (as when a flea ingests plague bacilli from an infected individual or animal and contaminates a susceptible host when it feeds again; the organism is not changed while in the flea). The other form of internal transmission is called biologic. In this form, the organism is changed biologically during its passage through the vector (for example, malaria parasites in the mosquito vector).

An infectious agent may be transmitted by more than one route. For example, Salmonella may be transmitted by a common vehicle (food) or by contact spread (human carrier). Francisella tularensis may be transmitted by any of the four routes.

The third link in the chain of infection is the host. The organism may enter the host through the skin, mucous membranes, lungs, gastrointestinal tract, or genitourinary tract, and it may enter fetuses through the placenta. The resulting disease often reflects the point of entrance, but not always: meningococci that enter the host through the mucous membranes may nonetheless cause meningitis. Development of disease in a host reflects agent characteristics (see above) and is influenced by host defense mechanisms, which may be nonspecific or specific.

Nonspecific defense mechanisms include the skin, mucous membranes, secretions, excretions, enzymes, the inflammatory response, genetic factors, hormones, nutrition, behavioral patterns, and the presence of other diseases. Specific defense mechanisms or immunity may be natural, resulting from exposure to the infectious agent, or artificial, resulting from active or passive immunization (see Ch. 8 ).

The environment can affect any link in the chain of infection. Temperature can assist or inhibit multiplication of organisms at their reservoir; air velocity can assist the airborne movement of droplet nuclei; low humidity can damage mucous membranes; and ultraviolet radiation can kill the microorganisms. In any investigation of disease, it is important to evaluate the effect of environmental factors. At times, environmental control measures are instituted more on emotional grounds than on the basis of epidemiologic fact. It should be apparent that the occurrence of disease results from the interaction of many factors ( Table 9-2 ). Some of these factors are outlined here.

General Factors That Influence the Occurence of Infectious Disease.

The three major epidemiologic techniques are descriptive, analytic, and experimental. Although all three can be used in investigating the occurrence of disease, the method used most is descriptive epidemiology. Once the basic epidemiology of a disease has been described, specific analytic methods can be used to study the disease further, and a specific experimental approach can be developed to test a hypothesis.

Descriptive Epidemiology

In descriptive epidemiology, data that describe the occurrence of the disease are collected by various methods from all relevant sources. The data are then collated by time, place, and person. Four time trends are considered in describing the epidemiologic data. The secular trend describes the occurrence of disease over a prolonged period, usually years; it is influenced by the degree of immunity in the population and possibly nonspecific measures such as improved socioeconomic and nutritional levels among the population. For example, the secular trend of tetanus in the United States since 1920 shows a gradual and steady decline.

The second time trend is the periodic trend. A temporary modification in the overall secular trend, the periodic trend may indicate a change in the antigenic characteristics of the disease agent. For example, the change in antigenic structure of the prevalent influenza A virus every 2 to 3 years results in periodic increases in the occurrence of clinical influenza caused by lack of natural immunity among the population. Additionally, a lowering of the overall immunity of a population or a segment thereof (known as herd immunity) can result in an increase in the occurrence of the disease. This can be seen with some immunizable diseases when periodic decreases occur in the level of immunization in a defined population. This may then result in an increase in the number of cases, with a subsequent rise in the overall level of herd immunity. The number of new cases then decreases until the herd's immunity is low enough to allow transmission to occur again and new cases then appear.

The third time trend is the seasonal trend. This trend reflects seasonal changes in disease occurrence following changes in environmental conditions that enhance the ability of the agent to replicate or be transmitted. For example, food-borne disease outbreaks occur more frequently in the summer, when temperatures favor multiplication of bacteria. This trend becomes evident when the occurrence of salmonellosis is examined on a monthly basis ( Fig. 9-2 ).

An example of a disease showing a seasonal trend. Reported human Salmonella isolations, by 4-week average, in the United States from 1968 to 1980.

The fourth time trend is the epidemic occurrence of disease. An epidemic is a sudden increase in occurrence due to prevalent factors that support transmission.

A description of epidemiologic data by place must consider three different sites: where the individual was when disease occurred; where the individual was when he or she became infected from the source; and where the source became infected with the etiologic agent. Therefore, in an outbreak of food poisoning, the host may become clinically ill at home from food eaten in a restaurant. The vehicle may have been undercooked chicken, which became infected on a poultry farm. These differences are important to consider in attempting to prevent additional cases.

The third focus of descriptive epidemiology is the infected person. All pertinent characteristics should be noted: age, sex, occupation, personal habits, socioeconomic status, immunization history, presence of underlying disease, and other data.

Once the descriptive epidemiologic data have been analyzed, the features of the epidemic should be clear enough that additional areas for investigation are apparent.

Analytic Epidemiology

The second epidemiologic method is analytic epidemiology, which analyzes disease determinants for possible causal relations. The two main analytic methods are the case-control (or case-comparison) method and the cohort method. The case-control method starts with the effect (disease) and retrospectively investigates the cause that led to the effect. The case group consists of individuals with the disease; a comparison group has members similar to those of the case group except for absence of the disease. These two groups are then compared to determine differences that would explain the occurrence of the disease. An example of a case-control study is selecting individuals with meningococcal meningitis and a comparison group matched for age, sex, socioeconomic status, and residence, but without the disease, to see what factors may have influenced the occurrence in the group that developed disease.

The second analytic approach is the cohort method, which prospectively studies two populations: one that has had contact with the suspected causal factor under study and a similar group that has had no contact with the factor. When both groups are observed, the effect of the factor should become apparent. An example of a cohort approach is to observe two similar groups of people, one composed of individuals who received blood transfusions and the other of persons who did not. The occurrence of hepatitis prospectively in both groups permits one to make an association between blood transfusions and hepatitis; that is, if the transfused blood was contaminated with hepatitis B virus, the recipient cohort should have a higher incidence of hepatitis than the nontransfused cohort.

The case-control approach is relatively easy to conduct, can be completed in a shorter period than the cohort approach, and is inexpensive and reproducible; however, bias may be introduced in selecting the two groups, it may be difficult to exclude subclinical cases from the comparison group, and a patient's recall of past events may be faulty. The advantages of a cohort study are the accuracy of collected data and the ability to make a direct estimate of the disease risk resulting from factor contact; however, cohort studies take longer and are more expensive to conduct.

Another analytic method is the cross-sectional study, in which a population is surveyed over a limited period to determine the relationship between a disease and variables present at the same time that may influence its occurrence.

Experimental Epidemiology

The third epidemiologic method is the experimental approach. A hypothesis is developed and an experimental model is constructed in which one or more selected factors are manipulated. The effect of the manipulation will either confirm or disprove the hypothesis. An example is the evaluation of the effect of a new drug on a disease. A group of people with the disease is identified, and some members are randomly selected to receive the drug. If the only difference between the two is use of the drug, the clinical differences between the groups should reflect the effectiveness of the drug.

• Epidemic Investigation

An epidemic investigation describes the factors relevant to an outbreak of disease; once the circumstances related to the occurrence of disease are defined, appropriate control and prevention measures can be identified. In an epidemic investigation, data are collected, collated according to time, place, and person, and analyzed and inferences are drawn.

In the investigation, the first action should be to confirm the existence of the epidemic by noting from past surveillance data the number of cases suspected and comparing this with the number of cases initially reported. Additionally, the investigator should discuss the occurrence of the disease with physicians or others who have seen or reported cases after examining patients and reviewing laboratory and hospital records. These diagnoses should then be verified. A case definition should be developed to differentiate patients who represent actual cases, those who represent suspected or presumptive cases, and those who should be omitted from further study. Additional cases may be sought or additional patient data obtained, and a rough case count made.

This initial phase consists basically of collecting data, which then must be organized according to time, place, and person. The population at risk should be identified and a hypothesis developed concerning the occurrence of the disease. If appropriate, specimens should be collected and transported to the laboratory. More specific studies may be indicated. Additional data from these studies should be analyzed and the hypothesis confirmed or altered. After analysis, control and prevention measures should be developed and, as far as possible, implemented. A report containing this information should be prepared and distributed to those involved in investigating the outbreak and in implementing control and/or prevention measures. Continued surveillance activities may be appropriate to evaluate the effectiveness of the control and prevention measures.

In the United States, the CDC assists state health departments by providing epidemiologic and laboratory support services on request. Its assistance supports disease investigations and diagnostic laboratory activities and includes various training programs conducted in the states and at the CDC. A close working relationship exists between the CDC and state health departments. Additionally, physicians frequently consult with CDC personnel on a variety of health-related problems and attend public health training programs.

The use of epidemiology to characterize a disease before its etiology has been identified is exemplified by the initial studies of acquired immune deficiency syndrome (AIDS). The first cases came to the attention of the CDC late in 1981 when an increase was observed in requests for pentamidine for treatment of Pneumocystis carinii pneumonia. This initiated specific surveillance activities and epidemiologic studies that provided important information about this newly diagnosed disease.

Initial symptoms include fever, loss of appetite, weight loss, extreme fatigue, and enlargement of lymph nodes. A severe immune deficiency then develops, which appears to be associated with opportunistic infections. These infections include P carinii pneumonia, diagnosed in 52 percent of cases; Kaposi sarcoma in 26 percent of cases; and both P carinii pneumonia and Kaposi sarcoma in 7 percent of cases. The remaining 15 percent of AIDS patients have other parasitic, fungal, bacterial, or viral infections associated with immunodeficiencies. Among the first 2,640 cases reported to the CDC, there were 1,092 deaths, a case-fatality rate of 41 percent. Approximately 95 percent of the cases were male; 70 percent were 20 to 49 years of age at the time of diagnosis. Approximately 40 percent of the cases were reported from New York City, 12 percent from San Francisco, 8 percent from Los Angeles, and the remainder from 32 other states. Cases were reported from at least 16 other countries. Among the 90 percent of patients who were categorized according to possible risk factors, those at highest risk were homosexuals or bisexuals (70 percent), intravenous drug abusers ( 17 percent), Haitian entrants into the United States (9.5 percent), and persons with hemophilia (1 percent).

Analysis of these initial data, collected before the etiologic agent of AIDS was identified, supported the hypothesis that transmission occurred primarily by sexual contact, receipt of contaminated blood or blood products, or contact with contaminated intravenous needles. Spread through casual contact did not seem likely. The epidemiologic data indicated that AIDS was an infectious disease. It has now been determined that AIDS results from infection with a retrovirus of the human T cell leukemia/lymphoma virus family, which has been designated human immunodeficiency virus type I (HIV-l). The initial hypotheses have been proven as shown by analysis of data subsequently collected.

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