What Does an Epidemiologist Do?

Published on: Nov 20, 2023

Despite all the media attention epidemiologists received during the COVID-19 pandemic, you may still wonder, “What does an epidemiologist do?”. Epidemiologists, commonly referred to as “disease detectives”, play a crucial role in keeping populations safe from public health threats. While epidemiologists are commonly known for working to prevent the spread of infectious diseases, they also play an integral role in preventing chronic disease, developing health treatments, and mitigating the impacts of injury, environmental health hazards, natural disasters, and bioterrorism. The diverse opportunities in this field are expected to increase over time. According to the Bureau of Labor Statistics, employment opportunities in epidemiology are projected to grow 26 percent from 2021 to 2031, which is much faster than the average for all occupations1.  

This article aims to provide some clarity on what epidemiologists do. We will highlight different career paths in the field of epidemiology, describe the main responsibilities of epidemiologists, and provide tips to help you further explore whether a career as an epidemiologist is right for you. 

A quick review of the role of epidemiology in public health

Epidemiology is the scientific foundation of public health practice. It is the study of how diseases and other health-related events develop and spread throughout a population2. Applied epidemiology is a term that is sometimes used to describe the application of epidemiologic principles to address public health issues. Applied epidemiologists work to assess, monitor, investigate and prevent these events. To learn more about the field of epidemiology and its role in public health, read our core discipline review on epidemiology.

What are common responsibilities and duties of an epidemiologist?

Epidemiologists work to understand what data is telling us about the health outcomes of a population. That being said, there are common tasks that most epidemiologists have as part of their work day:

  • Data Collection, Management, and Analysis:

    Epidemiologists conduct research and monitor data to understand how diseases are affecting the human population. Data related tasks include managing large sets of medical data and conducting statistical analyses. Depending on their field of work, the type of data collected and analyzed can vary greatly.

  • Research Design:

    Epidemiologic studies are the foundation of disease control and prevention. In this career, you can expect to apply epidemiological methods to research in a variety of settings, including outbreak prevention and clinical trials. Research epidemiologists, such as those investigating specific issues in an academic setting, are more likely to oversee a research project from start to finish, but all epidemiologists apply principles of research design in their work.   

  • Meetings and Report Writing:

    Like most public health professionals, epidemiologists are often a part of collaborative, interdisciplinary teams. As disease investigators, epidemiologists will need to communicate findings to various audiences, including health management professionals, analysts, and government officers. 

How do the duties of an epidemiologist vary by work setting and specialization?

While epidemiologists share many common tasks, there is a lot of variation among roles depending on the subject matter, geographic scope, and professional industry they are working in. Below you’ll find a more in-depth look at the responsibilities of epidemiologists working in various fields. 

What does an epidemiologist working in Disaster and Outbreak Response do?

Some epidemiologists are involved in work that is in direct response to an emerging health threat. Some positions in this field include: 

Field Epidemiologist: The work of these epidemiologists can often be distinguished by its pace and setting3. Field epidemiologists respond to urgent health threats, and often travel to affected sites in order to investigate and help resolve disease outbreaks and other public health problems. Field epidemiologists often conduct descriptive studies, which are done without changing the environment for informational purposes4, to better understand the issue before forming a hypothesis and conducting analytical studies. Tasks related to field epidemiology include:

  • Interviewing and Contact Tracing: During an active outbreak, epidemiologists contact people in the affected population to understand who has the disease, how they may have contracted it, and provide guidance for preventing spread.

  • Field Observation: Field epidemiologists are deployed during active outbreaks to meet with community members and collect biological samples to identify the health threat.

Disaster Epidemiologist: Disaster epidemiologists conduct field observations to understand the health impact resulting from a disaster and prevent future risk. Events studied include natural disasters, like fires, floods, and hurricanes, and man-made disasters, such as incidents of bioterrorism. Disaster epidemiologists monitor short and long term impacts in the affected areas and provide timely solutions to decision makers that support recovery and emergency response efforts5 .

Environmental Epidemiologist: Environmental exposures also pose a threat to human health. Epidemiologists in this field play a critical role assessing human exposure to biological, chemical, and physical stressors and the resulting diseases that occur from them6. Someone in this field may work for a national institute like the Environmental Protect Agency, or within a local or state health department. Tasks more specific to environmental epidemiologists include:

  • Chemical Testing: They may conduct ecological tests on features of the environment, such as soil and water, or biological tests on affected people, like blood level exposure tests. For example, an epidemiologist assessing environmental exposures to lead in a city may work with a team to collect samples of lead paint in homes, as well as with physicians to identify children with elevated blood lead levels (EBLLs). 

  • Developing Environmental Advisories: An environmental epidemiologist can use information from contaminant and toxin evaluations to inform official environmental reports like local fish consumption advisories12.  

What does an epidemiologist working with Communicable and Infectious Diseases do?

Other epidemiologists work specifically within the domain of communicable diseases. These roles include:

Infectious Disease Epidemiologist: These epidemiologists work to prevent future outbreaks. Case surveillance happens at the local and state level– there are about 120 notifiable diseases that health departments track and report to the CDC for nationwide surveillance7. Infectious disease epidemiologists can therefore work under many geographic scopes, including at the local, state, regional, federal, and global levels, in settings ranging from a local health department to the World Health Organization. In a research setting, they might also work to understand specific diseases through investigations funded by an academic or research institution.

Veterinary Epidemiologist:  An estimated 6 out of 10 human infectious diseases can be spread from animals8. This field requires an extensive knowledge of animal health and is typically pursued by veterinarians. After pursuing a Doctor of Veterinary Medicine (DVM), a veterinarian may also pursue a Master of Public Health in epidemiology in order to strengthen their understanding of public health research methods. 

Infection Control Epidemiologist: Infection control is a crucial part of keeping hospital patients, staff, and visitors safe. Also referred to as hospital epidemiologists, these epidemiologists typically have clinical degree, such as a medical (MD or DO) or nursing (RN or DNP) degree. They lead infection prevention efforts in hospitals with tasks including9

  • Surveillance: Infection control professionals must monitor cases of infectious disease with the health center and lead preventative action where needed 

  • Health policy and protocol development: Hospitals have sanitation protocols for activities such as handwashing, masking, and tool cleaning that aim to reduce the chance of spreading infection. Hospital epidemiologists help develop and enforce these protocols. 

  • Cost-Benefit Analyses: In the context of a hospital or medical center, epidemiologists must understand the costs associated with implemented measures and be able to present

What does an epidemiologist working with non-communicable diseases do?

Epidemiologists are not only limited to studying active outbreaks or infectious diseases. Other specialists within the field include:

  • Molecular Epidemiologist: There is a growing understanding that disease determinants also include genetic factors, which are often studied on the molecular level. These epidemiologists work at the interaction of genetics, biology, and epidemiology to understand how genes, molecules and pathways impact disease transmission, especially in chronic diseases10

  • Cancer Epidemiologist: Relatedly, the study of cancer deals with understanding the different risk factors related to cancer, including genetic risk and environmental exposure. 

  • Pharmaceutical Epidemiologist: Pharmaceutical companies are also potential workplaces for epidemiologists, as they play an important role in clinical trials and may be involved in several parts of treatment development. In early phases of development, epidemiological research can be used to understand the impact of health issues and potential treatments in a population of interest. Epidemiologists can also help develop drug and medical device efficacy trials.

As you can see, there are many fields and subspecialities within epidemiology. Check out the video links below to see a ‘day-in-the-life’ of two epidemiologists working in different fields:

Day in the Life: MSF Outbreak Epidemiologist in Global Health

Day in the Life: City Government Epidemiologist

Who do epidemiologists typically collaborate with on a daily basis at work?

No matter what their specialty is, epidemiologists do not work in isolation. They are often part of diverse teams that all support data collection, analysis, and distribution. Professionals that epidemiologist typically collaborate with at work include:

  • Health care Professionals:

    Doctors, nurses and other health science professionals are front line biological data collectors and play a crucial role in epidemiological research. Health care professionals are trusted to accurately measure individual health data, which epidemiologists then analyze at the population level.

  • Healthcare Administration:

    Health system leaders, project managers, and other administrative staff often drive decisions around what information is collected and how epidemiological research will impact organizational policy. 

  • Other Researchers:

    Research teams often include other epidemiologists, medical professionals, research coordinators and assistants, and data analysts. 

  • Biostatisticians:

    While epidemiologists are required to be knowledgeable on statistical methods, they may also collaborate with biostatisticians, who are experts in understanding the appropriate analytical methods needed for the data sample at hand.

  • Government Officials:

    Depending on where they work, epidemiologists may be required to report their findings to the local or federal government. For example, a state epidemiologist that detects a case of syphilis must formally report this case to the Centers of Disease Control to ensure cases are being monitored nationally. 

  • Pharmacists:

    In the pharmaceutical setting, pharmacists provide industry specific knowledge on drugs, their common side effects, potential interactions, and other information that’s pertinent to clinical trials.  

Now that you have an answer to the question, “What does an epidemiologist do”?, you may have another question– “What should I do if I think I want to pursue a career as an epidemiologist?”.

Advice for someone considering a career as an epidemiologist:

  • Seek the appropriate education:

    Firstly, if you are considering a career as an epidemiologist, you will want to make sure you have the education requirements needed to pursue the career. While some positions might require a doctoral degree, most will require a Master’s degree at minimum. Learn more about choosing the right MPH program for you.

  • Get some hands-on experience:

    Internships, fellowships, and research assistant positions can all provide you with valuable experience and glimpse at some of the day-to-day tasks of epidemiologists. If you are pursuing a degree in epidemiology, connect with researchers within the epidemiology department to see if they have positions available for graduate students. The Centers for Disease Control (CDC) and National Institute of Health (NIH) offer training opportunities for epidemiology students and post-graduates. 

  • Stay informed:

    The internet is a powerful tool, and you should use it to your advantage. To integrate some casual epidemiology-related reading into your daily routines, consider following public health organizations you find interesting on Twitter, LinkedIn, Instagram, YouTube and other platforms. 

  • Talk to an epidemiologist!

    There’s no better way to understand what it is like to work in a field than to talk to someone in it. Try connecting with epidemiologists or professionals in a related field to set up an informational interview. State and local health departments often have contact information for the epidemiology department publicly available online. If your alma mater has an alumni network or LinkedIn page, you could also connect with epidemiologists using those platforms. 

If you’re interested in using health data to understand public health issues, epidemiology may be a good fit for you. Finding an MPH program is a great step forward in jumpstarting your future career as an epidemiologist.

About the Authors

Written by:

Wandia Mureithi, MPH

Wandia Mureithi, MPH is a public health project manager working in research and evaluation. Wandia received her Master’s in Public Health from Drexel University in 2022. Since beginning her career in 2018, she has been engaged in research projects and program evaluations related to sexual health, human trafficking prevention, tobacco prevention, opioid misuse treatment, and diabetes prevention. 

In addition to her work projects, Wandia is interested in reducing maternal and child health disparities and advancing social justice in public health. 

Opinions and information published by the author here on MastersPublicHealth.com are of my own and do not necessarily represent the views or opinions of my employer or other organizations for my designated roles.

Wandia Mureithi portrait photograph

Wandia Mureithi, MPH

Education: Drexel University Dornsife School of Public Health

Reviewed by:

Katherine Paul, MPH

Katherine Paul, MPH is a senior project manager at a leading medical communications and publications organization. She supports multidisciplinary teams handling large-scale accounts, the deliverables of which improve health outcomes and patient well-being. Ms. Paul holds a Master of Public Health (MPH) degree in Health Promotion from Columbia University, Mailman School of Public Health and passed the Certified Health Education Specialist (CHES) shortly after graduation. She holds a Bachelor of Arts degree in Sociology from Dickinson College.

Ms. Paul previously worked at a public health non-profit where she managed all aspects of diverse health-related projects, including the implementation of a randomized controlled clinical trial on sexual health for teens with developmental disabilities, as well as the evaluation of a statewide tobacco cessation program with more than 20,000 annual cases. She has developed and delivered posters and presentations at national conferences including the American Public Health Association (APHA) annual meeting. 

Opinions and information published by the author here on MastersPublicHealth.com are of my own and do not necessarily represent the views or opinions of my employer or other organizations for my designated roles.

Katherine Paul

Katherine Paul, MPH

Editorial Lead

Education: Columbia University, Mailman School of Public Health

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