Given the limited availability of serological testing to date, the seroprevalence of SARS-CoV-2-specific antibodies in different populations has remained unclear. Here, we report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seroreactivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors in early April 2020. We additionally describe the longitudinal dynamics of immunoglobulin-G (IgG), immunoglobulin-M (IgM), and in vitro neutralizing antibody titers in COVID-19 patients. The median time to seroconversion ranged from 10.3–11.0 days for these 3 assays. Neutralizing antibodies rose in tandem with immunoglobulin titers following symptom onset, and positive percent agreement between detection of IgG and neutralizing titers was >93%. These findings emphasize the importance of using highly accurate tests for surveillance studies in low-prevalence populations, and provide evidence that seroreactivity using SARS-CoV-2 anti-nucleocapsid protein IgG and anti-spike IgM assays are generally predictive of in vitro neutralizing capacity. Highly accurate antibody tests for SARS-CoV-2 are needed for surveillance in low-prevalence populations. Here, the authors find seroprevalence of less than 1% in two San Francisco Bay Area populations at the beginning of April, and that seroreactivity is generally predictive of in vitro neutralising activity.
【저자키워드】 SARS-CoV-2, viral infection, Diagnostic markers, Epidemiology, 【초록키워드】 IgG, IgM, antibody, in vitro, Population, Protein, Seroconversion, SARS-CoV-2 seroprevalence, Immunoglobulin, Surveillance, Serological testing, neutralizing capacity, Antibody test, COVID-19 patients, Anti-spike, Neutralizing antibody titer, Neutralising activity, Neutralizing titer, Evidence, blood donor, Predictive, San Francisco Bay, symptom onset, SARS-CoV-2-specific antibody, median time, indication, positive, populations, assays, remained, less, hospitalized patient, Area, ranged, 【제목키워드】 Neutralizing activity, SARS-CoV-2 seroprevalence, Patient, Blood, Donor,