What is Epidemiology?

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Epidemiologists working in a laboratory.

In December 2019, a new highly contagious coronavirus was identified in Wuhan, China. Within weeks, that virus, ultimately dubbed COVID-19, began spreading across the globe. A worldwide pandemic ensued. According to an article published by Becker’s Hospital Review, by the end of 2020 nearly 346,000 people in the U.S. had died from COVID-19, although it’s believed the virus may have killed many more.

When a new infectious virus or disease is discovered, scientists work to identify the source of the outbreak and monitor and track new cases. These professionals — epidemiologists — work to learn more about the disease, such as the length of its incubation period, (i.e., how long a person is infected before they start to show symptoms), how long infected persons are contagious, and which medical treatments are most effective. Individuals who choose this career path also research how to control the spread of the disease and, if possible, how to prevent another outbreak from happening in the future.

Health care professionals interested in advancing their careers in the area of epidemiology must start by developing the knowledge and skills to be successful. Completing an advanced degree, such as a master’s in public health, can prepare graduates to pursue jobs in this ever-growing field.

Epidemiology Defined

Exactly what is epidemiology? It is the scientific study of diseases and other health events, not on an individual level but within a specific population, such as a state, country, or continent. Although commonly associated with the study of communicable diseases, including COVID-19, epidemiology also covers chronic and environmental illnesses and even health issues resulting from accidents and violence.

The History of Epidemiology

Epidemiology dates to 400 B.C., when Greek physician Hippocrates attempted to pinpoint and dissect the sources of common ailments in his seminal essay “On Waters, Airs and Places.” The field of epidemiology has continued to progress ever since.

A breakthrough moment was the first known piece of epidemiological research — an analysis of metropolitan mortality data — commissioned and published in 1662 by London councilman John Graunt. Additionally, anesthesiologist John Snow is credited with founding the epidemiology profession with his work during the cholera outbreaks in London’s Golden Square in 1854.

Epidemiology in Public Health

Epidemiologists are often referred to as disease detectives, as epidemiology plays a crucial role in public health. For example, epidemiological evidence is not only used to inform strategies to identify, treat, and prevent future outbreaks, but to improve screening and diagnosis, the quality of patient care, and the diagnosis and management of various diseases. Where physicians focus on individual patients, epidemiologists focus on the population at large. As such, the results of their work often influence public health debates and policy.

Roles and Careers in Epidemiology

Health care professionals interested in working in this field have a variety of career paths to choose from, including nutritional epidemiology, chronic disease epidemiology, and molecular epidemiology, among others.

Nutritional Epidemiology

What epidemiology does in the field of nutrition is study the relationship between dietary and nutritional factors and the occurrence of disease. Individuals in this field often develop dietary guidelines and recommendations for various populations. Nutritional epidemiologists study and establish the relationship between diet and disease by performing human metabolic studies and laboratory studies, among other research methodologies.

Chronic Disease Epidemiology

Chronic disease epidemiologists study ways to prevent and control chronic diseases, such as cancer, cystic fibrosis, diabetes, heart disease, and beyond. In addition to examining the natural history of chronic diseases and disorders, professionals in this field also research treatment and mitigation options.

Molecular Epidemiology

Molecular epidemiology examines patterns associated with disease transmission. Molecular epidemiologists study genetic or molecular markers to trace disease development, transmission rates, and the evolution of bacterial pathogens.

Epidemiologist Salary Ranges

Although the U.S. Bureau of Labor Statistics (BLS) doesn’t have data for specialty fields in epidemiology, it does provide average salary data for the field as a whole. It notes that as of May 2019, the median annual wage for epidemiologists in the U.S. was $79,990, although earners in the top 10% reported making more than $119,200 per year. Salary ranges vary based on several factors, such as experience level, job location, and industry. For example, the BLS notes that as of May 2019, the median annual wage for an epidemiologist who worked in scientific research and development was $99,770, where the median annual wage for epidemiologists employed at colleges, universities, and other schools was $62,440.

Future of Epidemiology

The BLS estimates that approximately 8,000 epidemiologists were working in the U.S. in 2019. It further projects that employment of epidemiologists is expected to grow 5% between 2019 and 2029, as demand rises from local and state governments and hospitals.  This growth rate is faster than the average for all occupations.

The need is ever present and growing for public health initiatives that are designed to eradicate noncommunicable diseases. A number of serious conditions continue to impact communities across the globe, most notably ischemic heart disease, chronic obstructive pulmonary disease, cancer, diabetes, and Alzheimer’s disease. On top of this, several illnesses that were thought to be eradicated are materializing again, according to the CDC, which announced in 2019 that the U.S. reported its highest number of measles cases since the eradication of the disease from the country in 2000.

The medical organizations, health care nonprofits, government agencies, and academic institutions tasked with addressing such public health issues need the help of trained professionals. Epidemiologists are capable of answering this call and leveraging their clinical abilities, organizational skills, and leadership experience to help patients suffering from noncommunicable diseases.

Gaining the Right Skills

Health care professionals interested in pursuing this career path should start by completing an advanced degree. In fact, the BLS notes that holding a graduate degree in an arena such as public health is a prerequisite to work in this field.

A strong Master of Public Health (MPH) program can offer the full range of technical and soft skills for success in the field, including data analysis, study design, and epidemiologic methods, as well as critical thinking and communication.  MPH students benefit from hundreds of hours of hands-on field experience, which allows them to apply their knowledge in real-world situations. Graduates often find that upon completion of the program, they’ve developed an understanding of how to measure the impact of illness and disease, address inequities in care and delivery, and observe changes to community health and safety.

Interested in Making a Difference in the Field of Epidemiology?

The online Master of Public Health program at Regis College offers an epidemiology concentration covering infectious and chronic disease epidemiology, along with a host of foundational courses such as health ethics, biostatistics, and health administration. The program is 100% online, helping returning students preserve a balance between their education, ongoing careers, and other obligations.

Are you ready to make a difference in the field of epidemiology? Contact Regis College today to learn more about the online MPH degree program.

Recommended Readings:

8 Environmental Factors that Affect Health

What Can I Do After Earning an MPH?

Exploring MPH Career Outcomes


AccessPharmacy, “Chapter 1. Introduction to Epidemiology and Public Health”

Becker’s Hospital Review, “1 Year Later: How COVID-19 Data Issues Have Persisted Since Beginning of Pandemic”

Centers for Disease Control and Prevention, “Lesson 1: Introduction to Epidemiology”

Centers for Disease Control and Prevention, “Measles Cases in the U.S. Are Highest Since Measles Was Eliminated in 2000”

Centers for Disease Control and Prevention, “What do State Chronic Disease Epidemiologists Do?”

Centers for Disease Control and Prevention, “What is Epidemiology?”

Centers for Disease Control and Prevention, “Who are Epidemiologists?”

The Conversation, “A Whole New Way of Doing Nutrition Research”

ScienceDirect, Molecular Epidemiology

U.S. Bureau of Labor Statistics, Epidemiologists