CDC Updates Definition of COVID-19 “Close Contact”

A CDC report published in October examines a case of COVID-19 that occurred in an employee of a Vermont correctional facility. During one eight-hour shift, the correctional officer was within six feet of an infected person an estimated 22 times for about 17 minutes of cumulative exposure. Seven days later, the employee became ill with symptoms consistent with COVID-19 and later tested positive for SARS-CoV-2.

The report prompted CDC to update its definition of what it means to be a “close contact” of someone with COVID-19, previously defined as someone who spent at least 15 consecutive minutes within six feet of an infected person. CDC now defines a close contact as “someone who was within six feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period.”

The asymptomatic incarcerated or detained persons to whom the employee was exposed arrived from an out-of-state correctional facility and were housed in a quarantine unit. They were tested for SARS-CoV-2 the same day the exposures occurred and received positive test results the following day. According to the report, the infected persons wore microfiber cloth masks during most interactions with the correctional officer but were unmasked during several encounters in cell doorways or in the recreation room. The employee wore a microfiber cloth mask, gown, and goggles during all interactions and gloves during most interactions.

Several factors suggest that the officer’s most likely exposures occurred through these brief workplace encounters, as he reported neither known close contact with persons with COVID-19 outside work nor travel outside Vermont during the 14 days before he became ill. In addition, the COVID-19 cumulative incidence in the county was relatively low—20 cases per 100,000 people—at the time the case was investigated.

View the full report on CDC’s website. The agency’s updated definition of “close contact” is also published online.