Contact tracing, active monitoring, quarantine & isolation

These four strategies have been proven over decades to reduce the spread of a wide range of contagious diseases, including COVID-19.

Contact tracing: Public Health Department employees interview a person already sick or who has tested positive with a contagious disease to figure out who else may have been exposed while the person was contagious. They then contact those people to let them know they have been exposed, and ask them to quarantine.

Active monitoring: Public health employees have daily contact with people who are in quarantine or isolation, usually by telephone. The public health worker checks on people’s symptoms, such as fever or cough, to see whether and how the disease develops and to recommend appropriate action.

Isolation: For people who likely are infected with a contagious disease, usually determined through symptoms or a lab test. The person not only stays home, but also stays away from other members of the household to prevent them from getting sick, too. For COVID-19, the day the person starts to have symptoms or tests positive is counted as day 0; isolation lasts 10 more full days, ending on day 11.

Quarantine: For people who have been exposed to a person with a contagious disease. People stay home and see whether they, too, develop symptoms of illness. If they do get sick, their quarantine time has included the virus’ incubation period — the time when a person can spread the virus before actually appearing sick. For COVID-19, quarantine lasts 14 days from the last day of exposure. However, most people can resume their normal activities after 10 days, with continued symptom monitoring through day 14.