Quarantine is a set of measures that are designed to prevent the spread of communicable diseases and environmental toxins within an area. It is often a key component in the preparation of disaster responses and public health emergency operations.

In quarantine, a person is confined to their home or other designated location and is monitored for signs and symptoms of infection. Contact surveillance may involve a passive approach (informing contacts to seek medical attention if they develop any symptoms) or an active approach (contacts being directly assessed daily for signs and symptoms by health workers).

Successful quarantine requires a complex interplay of law enforcement, first responders and deployable government services workers, affected individuals, community leaders, local businesses, and transportation, education, and public health staffs. These partners must be well trained and prepared for their roles in the implementation of movement restrictions and other containment strategies.

While much of the COVID-19 quarantine effort has been focused on home-based isolation, designated quarantine facilities are also required in some circumstances, especially for large numbers of high-risk people such as health-care and ambulance personnel. These quarantine facilities need to be designed to accommodate the specific needs of these people and the specific disease transmission risks, with an emphasis on reducing the risk of psychological distress for quarantined individuals.