By Cynthia Carr, Epidemiologist

A few months ago during a casual conversation, I was asked, “What do you do exactly?” This was not a unique question. I am an epidemiologist, and before this very challenging COVID-19 crisis, almost no one (including my parents) knew what I did. Unfortunately, the term epidemiology has become all too common due to COVID-19; however, on the plus side, maybe through this some of you will have discovered a new potential career in community health.

Origins of Epidemiology

Epidemiology focuses on finding patterns of disease by looking at people, place and time.

Everyone knows John Snow, right? No, not the hero from Game of Thrones… I mean Dr. John Snow, who is considered the “father of epidemiology”.

In the 1800s, the infectious disease cholera became a major health threat, killing many people. There was a terrible outbreak in London, England, around 1854. People thought the disease was from the noxious-smelling air. But Dr. Snow questioned why only people from a certain area of London were getting sick when the air smelled terrible everywhere in the city.

He started talking to people who were sick so that he could determine what they all had in common. He noticed they all lived or worked in the same area… and they all got their drinking water from the Broad Street Pump.

The water in the pump looked and tasted just fine, but it carried the very dangerous parasite that caused cholera. His findings led to changes in water safety and sanitation around the world, saving millions of lives!

This is an example of a serious health risk that we cannot see or taste. Just like viruses such as COVID-19, they are difficult to deal with because people don’t know when or where they come in contact with them until they become infected or sick.

What Does an Epidemiologist Do?

Epidemiologists work to find what is the source of an illness. That is, we work in public health as “medical detectives” to find out what causes illness so that we can prevent it.

We use this information to do many things, such as:

  • Planning ahead to prevent illness by encouraging vaccinations, and watching health or illness developments in other countries.
  • Developing public health messages and support programs; for example, proving the link between smoking and the high risk of developing lung cancer and heart disease later in life, which led to educational campaigns, support programs and the banning of cigarette advertisements.
  • Developing public health and safety policies, such as safe driving practices. Epidemiologists are the ones who collected data to show the much higher rates of injuries and deaths among people driving too quickly or not wearing seat belts.

What Do I Need to Study to Become an Epidemiologist?

There is a wide range of people who become epidemiologists, and they work in many different areas. No matter your background, you do need a minimum of a Master’s degree in this field, even if you are already a doctor.

My background is a Bachelor of Arts in Psychology and a Master’s Degree in Health Policy. I fell in love with epidemiology and completed the Master of Science in Community Health and Epidemiology at Queen’s University. Other students in my class were doctors, nurses, physiotherapists, pharmacists and students who had a science background. I was probably one of the only ones without a really hard science background, but I did have several statistics courses, which you definitely need to get into this field.

What Kind of Job Can I Get?

The opportunities in this field are endless. You can work for your community to collect evidence to support funding requests for health programs and services. You can help develop those programs and then use data to show if the programs helped people get healthy or stay healthy.

There are many epidemiologists that work for the government, for the World Health Organization, for hospitals, community care and university research—the list goes on and on. You could be a doctor who focuses on researching illness prevention instead of treating patients; you could be a pharmacist who wants to conduct research into new vaccines or drugs to treat illness; you could be a medical health officer who focuses on health prevention and education. All these fields need epidemiologists!

Find Your Passion

My focus has always been working with communities and programs to look at health risk factors and then find solutions. My passion is using my education to learn about what matters most to community members, to collect the data to show why it really is a priority issue. This could be survey data, interviews, and then data about how you use medical travel, where you go for services, what would help to have in the community, and how lives are affected by access to healthy food and recreational activities.

Do you enjoy data, statistics and making graphs? Are you excited by figuring out puzzles and patterns? Do you like the idea of answering questions that can impact the health and well-being of others? If you said yes to these questions and you like the idea of working in health (but are not so sure about blood and guts) then epidemiology might be for you! You can make a real difference by joining the network of public health professionals in preventing illness so that we can all live the longest, healthiest and happiest lives possible.

Cynthia Carr is an epidemiologist and a principal consultant with EPI Research Inc. For more than 25 years, she has been using data to support program planning, evaluation and knowledge exchange. For more info, visit