How do I know if I have been exposed to someone who has COVID-19?

The CDC now recommends case investigation and contact tracing only in health care settings and certain high-risk congregate settings. Persons who have had recent confirmed or suspected exposure to an infected person should wear a mask for 10 days around others when indoors in public and should receive testing ≥5 days after exposure (or sooner, if they are symptomatic), irrespective of their vaccination status.