High Seroprevalence of Anti-SARS-CoV-2 Antibodies in Chelsea, Massachusetts
Vivek Naranbhai, Christina C. Chang, Wilfredo F. Garcia Beltran, Tyler E. Miller, Michael G. Astudillo, Julian A. Villalba, Diane Yang, Jeffrey A. Gelfand, B Bernstein, Jared Feldman, Blake M. Hauser, Timothy M. Caradonna, Galit Alter, Mandakolathur R. Murali, Rashmi Jasrasaria, Joan Quinlan, Dean Xerras, Joseph R. Betancourt, David N. Louis, Aaron G. Schmidt, Jochen K. Lennerz, Mark C. Poznansky, A. John Iafrate
Abstract
SARS-CoV-2 antibody testing allows quantitative determination of disease prevalence, which is especially important in high-risk communities. We performed anonymized convenience sampling of 200 currently asymptomatic residents of Chelsea, the epicenter of COVID-19 illness in Massachusetts, by BioMedomics SARS-CoV-2 combined IgM-IgG point-of-care lateral flow immunoassay. The seroprevalence was 31.5% (17.5% IgM+IgG+, 9.0% IgM+IgG-, and 5.0% IgM-IgG+). Of the 200 participants, 50.5% reported no symptoms in the preceding 4 weeks, of which 24.8% (25/101) were seropositive, and 60% of these were IgM+IgG-. These data are the highest seroprevalence rates observed to date and highlight the significant burden of asymptomatic infection.