Prevalence of sars-cov-2 antibodies after first 6 months of covid-19 pandemic, portugal

Abstract

In September 2020, we tested 13,398 persons in Portugal for antibodies against severe acute respiratory syndrome coronavirus 2 by using a quota sample stratifi ed by age and population density. We found a seroprevalence of 2.2%, 3-4 times larger than the offi cial number of cases at the end of the first wave of the pandemic.