Potential Transmission of SARS-CoV-2 from an Asymptomatic Carrier

The current outbreak of COVID-19 that began in Wuhan, China, has infected thousands of people, but questions remain about the infectivity, infectious period, and mechanisms of transmission.

In this study, investigators report a family cluster of five patients who likely acquired infection with SARS-CoV-2 (the virus causing COVID-19) from an asymptomatic 20-year-old woman who lives in Wuhan and traveled to Anyang, China (approximately 673 kilometers from Wuhan). In Anyang, she had contact with two persons over a 3-day period and with another three persons on the third day of this period. Four days later, one of the contacts became symptomatic; the other four contacts became symptomatic over the ensuing 9 days. The suspected index person tested negative for SARS-CoV-2 by RT-PCR 16 days after arriving from Wuhan but tested positive 2 days later; yet she remained asymptomatic and had no evidence of infiltrates on chest CT performed the day before and three days after testing positive. She also had no elevation of C-reactive protein or any laboratory abnormalities. The five contacts all developed symptoms consistent with COVID-19; four were women aged 42 to 57 years old. All had positive RT-PCR testing for SARS-CoV-2 within 1 day after hospital admission and multifocal ground-glass opacities on chest CT.