Monitoring of Those Exposed to COVID-19 in the U.S.

In this report, public health researchers detail findings of active monitoring of people in the U.S. who had been exposed to COVID-19. As of February 26, 2020, 12 travel-related cases of COVID-19 and 3 cases in patients with no travel history had been diagnosed in the U.S. (plus 46 cases in repatriated citizens). For 10 of the travel-related cases, investigators identified 445 close contacts. During active symptom monitoring of these contacts for 14 days, 54 people (12%) developed symptoms concerning for COVID-19. Two of these, who were both household contacts, tested positive for SARS-CoV-2, yielding a symptomatic secondary attack rate of 0.45%.