Exposure is defined as contact with someone infected with the virus that causes COVID-19, in a way that increases the likelihood of getting infected with the virus, but a particular type of exposure called ‘close contact’ is of most concern.    An infected person can spread COVID-19 starting 2 days before they have any symptoms or, for asymptomatic people, 2 days before the positive specimen was collected.

Close contact exposure results from the proximity and duration of exposure and occurs when someone was less than 6 feet away from a contagious person for a cumulative total of 15 minutes or more over a 24-hour period (for example, three individual 5-minute exposures for a total of 15 minutes).

An important exception to the definition of close contact exposure exists in a K–12 indoor classroom setting or a structured outdoor setting where mask use can be observed (i.e., holding class outdoors with educator supervision).  Students who were between 3 to 6 feet of an infected student if both the infected student and the exposed student(s) correctly and consistently wore well-fitting masks the entire time are not considered to have had close contact.  This exception does not apply to teachers, staff, or other adults in the indoor classroom setting.