Public health departments around the world have several tools to combat disease outbreaks and pandemics. One of the most important is contact tracing. Health departments do this all the time, but they have never done it at a scale like we’re expecting to do over the next few months for COVID-19.

What is contact tracing?

Contact tracing has two steps. First, health department staff ask someone who is sick with a disease for the names of the people they have been around. These people are the sick person’s “contacts.” Second, health department staff notify these “contacts” that they may have been exposed to a disease, how they can take care of themselves, and how they can avoid spreading it to other people.

The Philadelphia Department of Public Health already conducts routine contact tracing for people who test positive for sexually transmitted infections and tuberculosis. We are currently developing a program to do contact tracing for people who have COVID-19.

How does the Health Department find out who is sick with COVID-19?

When people go to the doctor because they are sick, or to a testing site because they think they were exposed to COVID-19, medical professionals take a sample and send it off to a lab for testing. For certain diseases, like COVID-19, these labs are required to report the results to the local health department. 

What should someone who tests positive for COVID-19 do?

People who test positive for COVID-19 are sick with the disease. They will be notified that they are positive and that they should isolate themselves until they are no longer sick. The CDC has tips on how to safely isolate yourself. People should stay isolated until they have: 

  • Three days in a row with no fever, and
  • Their symptoms have improved, and
  • It’s been 10 days since symptoms first appeared.

What happens to the “contacts” who may have been exposed to a person sick with COVID-19?

The Health Department is developing a COVID-19 contact tracing program that will begin in July 2020. Contact tracing staff will call each person in Philadelphia who has tested positive, recommend that they isolate themselves, and ask who they have been around. The Health Department will then notify those “contacts” that they may have been exposed to COVID-19 and should take precautions to keep others around them safe. Contact tracing staff will always identify themselves as working for the Philadelphia Department of Public Health.

What should “contacts” do after they talk to the Health Department?

People who may have been exposed to someone with COVID-19 should do two things:

  • Monitor themselves for symptoms.
  • Try to stay away from other people, or quarantine.

Contact tracing staff will stay in touch with each person they contact for 14 days, every day. During these two weeks, people will be asked to check their temperature and limit their exposure to other people. This means staying away from work, limiting time outside of the home, and distancing from others inside their own home.