Alliance for Pandemic Preparedness

May 29, 2020

Evidence for Limited Early Spread of COVID-19 Within the United States, January – February 2020

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  • Syndromic surveillance, virus surveillance, phylogenetic analysis, and retrospectively identified cases provide evidence that sustained community transmission in the US may have begun before the detection of the first two non-travel related US cases in late February 2020, likely from a single importation from China, followed by several importations from Europe. 

Jorden et al. (May 29, 2020). Evidence for Limited Early Spread of COVID-19 Within the United States, January – February 2020. MMWR. https://doi.org/10.15585/mmwr.mm6922e1