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. 2021 Jan 5;4(1):e2033706. doi: 10.1001/jamanetworkopen.2020.33706

Table 1. Seroprevalence Estimates From SARS-CoV-2 Community Surveys in the US, April 10 to May 3, 2020.

Location Population (millions)a Sample size, No. SARS-CoV-2 seroprevalence (date of specimen collection), % Estimated No. of persons with SARS-CoV-2 infection Cumulative reported COVID-19 cases (date)b Underreporting multiplier
Infection Symptomatic
California (Los Angeles)5 9.4 863 4.6 (April 10-11) 434 031 13 069 (April 11) 33.2× 19.9×
Florida (Miami-Dade)6 2.7 1800 6.0 (April 15-20) 163 016 9657 (April 20) 16.9× 10.1×
Georgia (Dekalb-Fulton)7 1.8 696 2.5 (April 28-May 3) 45 581 5500 (May 3) 8.3×
Indiana (statewide)8 6.7 3658 2.8 (April 25-29) 188 502 17 756 (April 29) 10.6× 6.4×
New York (statewide)9 19.4 15 101 14.0 (April 14-28) 2 723 498 299 691 (April 28) 9.1× 5.5×
All NA Total: 22 118 NA NA NA Median: 10.6× (IQR, 9.1× to 16.9×) Median: 6.4× (IQR, 5.5× to 10.1×)

Abbreviations: COVID-19, coronavirus disease 2019; IQR, interquartile range; NA, not applicable; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

a

US Census Bureau quick factors (all-age population).

b

Cumulative reported COVID-19 cases derived from county and state health department websites.