Estimating infectiousness throughout SARS-CoV-2 infection course

May 25, 2021

View ORCID ProfileTerry C. Jones1,2,3,†, View ORCID ProfileGuido Biele4,5,†, View ORCID ProfileBarbara Mühlemann1,2, View ORCID ProfileTalitha Veith1,2, View ORCID ProfileJulia Schneider1,2, Jörn Beheim-Schwarzbach1, Tobias Bleicker1, Julia Tesch1, Marie Luisa Schmidt1, View ORCID ProfileLeif Erik Sander6, View ORCID ProfileFlorian Kurth6,7, View ORCID ProfilePeter Menzel8, View ORCID ProfileRolf Schwarzer8, View ORCID ProfileMarta Zuchowski8, Jörg Hofmann8, Andi Krumbholz9,10, Angela Stein8, View ORCID ProfileAnke Edelmann8, View ORCID ProfileVictor Max Corman1,2, View ORCID ProfileChristian Drosten1,2,*


Using viral load and viral replication in cell culture, Jones et al. evaluated the course of SARS-CoV-2 infectivity among patients with varying ages, genders, and symptom severity. The authors analyzed 936,423 RT-PCR results from patients between 0-100 years in Germany, from February 24, 2020 to April 2, 2021. In addition to age and gender, patients were sorted as pre-symptomatic, asymptomatic, and mildly symptomatic (PAMS). Patients who tested positive were sorted into three categories: hospitalized, PAMS, and other. Across all ages, hospitalized patients held higher viral loads than PAMS patients. The time between the start of viral shedding and peak viral load was estimated to be 4.3 days, indicating that infectivity can begin before patients experience symptoms of COVID-19. Patients infected with the B.1.1.7 strain of SARS-CoV-2 were estimated to have a 1 log10 higher first-positive viral load compared to those infected with a wild-type strain (meaning cell replication was 2.6 times more likely). The authors acknowledge that estimating viral load was difficult because samples were obtained at unknown points in the disease course of the tested individual, and it is possible that differences in behavior due to milder symptoms may have caused PAMS subjects to be tested later than hospitalized patients, on average. Overall, PAMS patients were found to have similar levels of infectivity has hospitalized patients, with the authors suggesting that individuals experiencing mild symptoms can still trigger outbreaks in communities.

Jones TC, Biele G, Mühlemann B, et al. Estimating infectiousness throughout SARS-CoV-2 infection course. Science 2021; published online May 25. DOI:10.1126/science.abi5273.

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