Alliance for Pandemic Preparedness

May 19, 2020

Substantial Underestimation of SARS-CoV-2 Infection in the United States Due to Incomplete Testing and Imperfect Test Accuracy

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  • Current confirmed COVID-19 case counts in the US underestimate the total burden of the SARS-CoV-2 due to incomplete testing, driven by limited test availability, which is restricted primarily to individuals with moderate to severe symptoms. Imperfect diagnostic accuracy of the tests also contributes to an undercount of cases.
  • Wu et al. estimated that there were 6,275,072 cumulative SARS-CoV-2 infections in the US, compared to 721,245 confirmed cases (1.9% vs. 0.2% of the population) as of April 18, 2020. The authors estimated that approximately 86% of this difference was due to incomplete testing, while 14% was due to imperfect test accuracy.

Wu et al. (May 18,2020). Substantial Underestimation of SARS-CoV-2 Infection in the United States Due to Incomplete Testing and Imperfect Test Accuracy. Pre-print downloaded May 19 from https://doi.org/10.1101/2020.05.12.20091744