Alliance for Pandemic Preparedness

July 8, 2020

The Implications of Silent Transmission for the Control of COVID-19 Outbreaks

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  • Moghadas et al. used agentbased modeling to quantify the number of transmissions attributable to asymptomatic and pre-symptomatic SARS-CoV-3 infections. Empirical studies suggest that the proportion of asymptomatic cases range from 18 to 31%. At the lower end, when 18% of infections are asymptomatic, they estimated that pre-symptomatic cases account for 48% of transmissions and asymptomatic infections account for 3% of transmissions. These estimates change slightly if 31% of infections are asymptomatic: pre-symptomatic and asymptomatic infections accounted for 47% 7% of transmissions, respectively. These finding suggest that isolation of all symptomatic cases is not sufficient to achieve epidemic control. 

Moghadas et al. (July 2020). The Implications of Silent Transmission for the Control of COVID-19 Outbreaks. PNAS. https://doi.org/10.1073/pnas.2008373117