Alliance for Pandemic Preparedness

May 8, 2020

Viral Kinetics of SARS-CoV-2 in Asymptomatic Carriers and Presymptomatic Patients



  • Kim et al. included 71 participants with laboratory-confirmed SARS-CoV-2 infection who were hospitalized for treatment or isolation and found that 3 were pre-symptomatic and 10 were entirely asymptomatic. Two of the three pre-symptomatic patients had very high levels of virus present during the incubation period (Ct value <20).  
  • The median time until the first negative RT-PCR (Ct >35) in the entirely asymptomatic carriers was 4.5 (range 2.5-9) days, and all asymptomatic carriers reached the first negative within 14 days after diagnosis. Patients who have COVID-19 may already be infectious before they exhibit symptoms, and 14 days of isolation after diagnosis may be sufficient in entirely asymptomatic cases 

Kim et al. (May 3, 2020). Viral Kinetics of SARS-CoV-2 in Asymptomatic Carriers and Presymptomatic Patients. International Journal of Infectious Diseases.