What Does an Epidemiologist Do?

When people get sick, doctors come to the rescue. When entire populations get sick, it’s epidemiologists’ time to shine.

That was never clearer than during the COVID-19 pandemic, when these behind-the-scenes scientists and public health experts stepped into the spotlight. When the public wanted to know how the infection passed from person to person, who was most at-risk, and what the rest of us could do to slow or halt the spread of the disease, epidemiology provided the answers.

Answering questions is a big part of epidemiology. To do it, these public health professionals gather emerging and historical medical data. They analyze data to identify patterns that can potentially show where a disease came from, how quickly it’s moving around the globe, where it will appear next, and what treatments are and aren’t working.

That’s not all they do, however. Some specialize in viral infections like COVID-19. Others spend their days researching occupational hazards, vulnerable populations, pharmaceuticals, or the genes that power viruses and bacteria.

The goal of all epidemiologists—regardless of specialty—is to find out more about why people get sick or die. They also help develop the procedures to decrease risk or prevent it entirely.

In this article, we answer the question “what does an epidemiologist do?” We also discuss:

• What is epidemiology?
• What are epidemiologists responsible for?
• Where do epidemiologists work?
• Types of epidemiologists
• Do different kinds of epidemiologists do different things?
• How do you become an epidemiologist?
• Are epidemiologists paid well for what they do?
• Who is most likely to succeed in this career?

What is epidemiology?

Epidemiology is the study of the distribution of diseases, injuries, and death in specific populations. It was once a branch of medicine; historically, epidemiologists were nearly all doctors. Today, however, epidemiologists are scientists who may or may not have an MD in addition to a master’s degree and/or doctoral degree.

Epidemiology forms one of the cornerstones of public health as a discipline. By studying who gets sick or dies, when they get sick or die, and where they get sick or die, we can learn a lot about what causes diseases and patterns of death, how diseases progress, which populations are most vulnerable, and how we can improve public health policy and practice. The work of epidemiologists often drives the development of new treatments in medicine and new initiatives in the public health sphere.

What are epidemiologists responsible for?

All epidemiologists conduct research or use that research to propose solutions to public health challenges and manage public health programs. Most, regardless of specialty, do some or all of the following:

• Analyze public health data
• Collect biological samples
• Collect public health data via surveys, interviews, and research
• Create proactive disease or disaster response plans
• Design clinical research studies
• Develop education outreach strategies
• Develop predictive models of disease
• Identify at-risk populations
• Manage public health initiatives
• Monitor the progress of public health programs
• Oversee and track the results of clinical trials
• Plan and direct public health studies
• Publish their findings in medical journals
• Research emerging public health issues
• Study public health concerns in the field
• Study the effects of drugs on patients
• Write up reports for drugmakers, policymakers, and doctors

Beyond that, what an epidemiologist’s day-to-day duties look like depends on whether they’re employed in the private sector, the regulatory arena, public policy, or research.

Where do epidemiologists work?

Epidemiologists work in applied public health, scientific research, drug development, and medicine. The majority of epidemiologists are employed by state and local government agencies, hospitals, and schools. Epidemiologists also work for employers like:

• Colleges and universities
• Federal agencies (e.g., the Centers for Disease Control and Prevention and the National Institutes of Health)
• Health departments at the state and local levels
• Hospitals and medical networks
• Insurance companies
• Medical and dental schools
• Nonprofit public health organizations
• Pharmaceutical development companies
• Public policy groups
• Research labs
• Think tanks

Types of epidemiologists

There are many types of epidemiologists because there are so many forces that influence public health. Many people wrongly assume that all epidemiologists study epidemic diseases. In fact, some epidemiologists study non-disease health conditions like high blood pressure, depression, diabetes, and obesity. There are even epidemiologists who focus on illnesses and deaths that happen on the job; they also study the impact of work environments on health.

Epidemiologists typically specialize in one or more public health areas. These areas include:

• Applied public health
• Cancer
• Cardiovascular
• Dental
• Diabetes
• Disaster
• Environmental health
• Global health
• Infectious disease
• Molecular
• Obesity and nutrition
• Pediatrics
• Prevention
• Psychiatry
• Substance abuse
• Veterinary
• Women’s health

Do different kinds of epidemiologists do different things?

Epidemiologists don’t just conduct surveys and crunch numbers all day. Research is definitely a big part of the job, but beyond that, epidemiologists in different specialties do very different things. For example:

• Cancer research: Some epidemiologists spend their careers searching for the causes of specific cancers and the risk factors that make populations more likely to get those cancers. Their findings help scientists develop new treatments and experts develop new public health recommendations.
• Clinical trial research: These epidemiologists work for drug companies and medical device manufacturers. They oversee or analyze the results of clinical trials to help find more effective medicines and medical devices and to reduce the number of adverse effects of these treatments.
• Field epidemiology: The epidemiologists who work for health departments and government agencies are dispatched when there are major disease outbreaks. Their job is to identify the illness, determine what’s causing it, and develop strategies to contain or stop the spread.
• Infection control: Some epidemiologists are focused on controlling the spread of diseases in hospitals and other medical facilities. These infection control epidemiologists look at everything from survey results to blood samples to prevent or halt the spread of conditions like MRSA.
• Molecular research: Epidemiologists who specialize in molecular epidemiology spend their days in research labs probing the DNA and other structures in the cells of disease-causing pathogens and organisms. Molecular epidemiologists have been instrumental in slowing the spread of diseases like HIV.
• Public health epidemiology: These public health experts work for agencies like the CDC and the FDA. They collect public health information, identify emerging health problems, and develop ways to keep populations healthy.
• Travel analysis: As more people travel for business and pleasure, the risk of a global pandemic increases. Travel epidemiologists track the spread of illnesses and diseases across national borders and create guidelines for safe international travel.

How do you become an epidemiologist?

To become an epidemiologist, you’ll need a bachelor’s degree, a master’s degree, and possibly also a doctoral degree.

There’s no one prescribed degree pathway for epidemiologists at the bachelor’s degree level. Many aspiring epidemiologists earn bachelor’s degrees in biology, health science, health informatics, or public health, but others study art, history, or business. Quite a few master’s degree programs in epidemiology have no specific degree prerequisites. Tulane University of Louisiana, for instance, states in its Master of Public Health (MPH) in Epidemiology program description that it welcomes applicants “without previous training or experience in public health.”

There are also multiple graduate degree pathways open to aspiring epidemiologists. The Department of Epidemiology of the University of Pittsburgh Graduate School of Public Health offers both a Master of Public Health in Epidemiology and a Master of Science in Epidemiology.

MPH and MS programs typically differ somewhat in focus. While there may be a lot of overlap in the curricula of these two degrees, the former tend to cover a much broader range of topics, including health policy, environmental health sciences, and social and behavioral sciences.

The curriculum in MS in Epidemiology programs, on the other hand, is usually tightly focused on the science of epidemiology and related statistical research methods. To choose between them, consider your goals. If you want to pursue a career in epidemiological research, the MS is probably the better choice. Opt for the MPH degree if you want to take a hands-on approach to tackling public health issues.

Some, but not all, epidemiologists go on to earn doctoral degrees—usually a PhD in Epidemiology, a Doctor of Public Health (DrPH) in Epidemiology, or a joint MD/PhD degree. The PhD is the most common choice; you’ll need one if you want to become a professor or qualify for higher-level clinical or research positions. Consider the DrPH if you want to advance into public health management. If, however, you would like to spend your career running clinical research studies and drug trials, the joint MD/PhD may be the best choice.

Are epidemiologists paid well for what they do?

Becoming an epidemiologist isn’t a fast road to riches, but epidemiologists do earn a comfortable living. The BLS reports that the average epidemiologist earns about $80,000 per year, and epidemiologists in specialty positions can earn more. The average epidemiologist research analyst’s salary is about $100,000 and infection control epidemiologists earn about $105,000. Epidemiologists who work in scientific research and development services tend to earn the most.

The top-earning 10 percent of epidemiologists earn more than $130,000. The lowest-paid epidemiologists tend to work in academia and in state and local government agencies.

Who is most likely to succeed in this career?

Epidemiology is like a puzzle. People are getting sick or dying, no one knows why, and it’s up to the epidemiologists to find out why and how. It’s not always easy, and the process can involve hitting a lot of frustrating dead ends.

Successful epidemiologists not only have an aptitude for medicine and analytical minds, but they’re also extremely good at dealing with significant, complex problems. Patience is definitely a virtue epidemiologists must possess. They also need skills in:

• Communication
• Critical thinking
• Data analysis
• Pattern identification
• Problem solving
• Reasoning
• Research
• Statistics

Epidemiologists have to be fascinated by disease processes and passionate about improving the health of populations. Specifically, they have to be intrigued enough to keep working, knowing they probably won’t ever receive the kinds of accolades doctors regularly receive. Carlo Urbani was the first person to identify SARS as a highly contagious disease. Max Theiler developed an important vaccine against yellow fever. Dr. Janet Elizabeth Lane-Claypon literally helped launch epidemiology as a discipline. Chances are you’ve never heard of any of them, even though together they’ve helped save more lives than thousands of doctors.

At the end of the day, epidemiologists do what they do not for the money or any prestige they might receive during pandemics or other health crises. They do it because they know they can make a real difference in medicine and public health.

Questions or feedback? Email editor@noodle.com