IF YOU ARE FULLY VACCINATED
CDC has updated its guidance for people who are fully vaccinated. See Recommendations for Fully Vaccinated People.
IMPORTANT UPDATE FOR SCHOOLS
CDC recommends schools continue to use the current COVID-19 prevention strategies for the 2020-2021 school year. Learn more
Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more

About COVID-19 Epidemiology

About COVID-19 Epidemiology

Investigating COVID-19: The Science Behind CDC’s Response

When a new infectious disease is discovered, scientists called epidemiologists work with other scientists to find who has it, why they have it, and what CDC can do about it. From the beginning of the COVID-19 outbreak, scientists at CDC and around the world have been working to:

virus solid icon

Identify the source of the outbreak

Epidemiologists went to the area in China where the disease first appeared and conducted surveys in the community and health facilities. They collected nose and throat specimens for lab analyses. These field investigations showed them who was infected, when they became sick, and where they had been just before they got sick—and ultimately led them to a possible source.

chart line icon

Monitor and track the disease

CDC keeps track of the number of COVID-19 cases and collects information on the disease from surveillance systems that report different kinds of data, such as new cases, hospitalizations, deaths, demographic information (like age, race/ethnicity, or sex), symptoms, and treatments.

microscope solid icon

Study the disease

CDC scientists use surveillance data, including information from antibody testing and other kinds of studies, to find out more about the disease, such as how long someone with COVID-19 is contagious, risk factors for severe illness, and which medical treatments are most effective.

people icon

Develop guidance for actions to slow the spread of the disease and lessen its impact

Using study findings, case counts, and surveillance, CDC publishes resources to help people in different risk groups (like healthcare workers or older people) stay safe in different settings (like grocery stores, home, or school). This guidance is constantly being updated as new information become available.

Terms to Know

Field Investigation: Study conducted in a defined population, including a community or setting where many people live close together, such as a prison.