SARS-CoV-2 seroprevalence in Chattogram, Bangladesh before a National Lockdown, March-April 2021

In a representative serosurvey conducted March-June 2021, 64.1% (95%CrI 60.0- 68.1%) of Sitakunda subdistrict (Bangladesh) had anti-SARS-CoV-2 IgG antibodies after adjusting for age, sex, household clustering and test performance. Before the surge of Delta, most of the population had been infected despite low incidence of virologically-confirmed COVID-19.