After the rapid spread of SARS-CoV-2 BA.5 Omicron lineage in Portugal, we developed a seroepidemiologic survey based on a sample of 3,825 residents. Results indicated that from April 27 through June 8, 2022, the estimated seroprevalence of SARS-CoV-2 nucleocapsid or spike IgG was 95.8%, which indicates a high level of protection.
Keywords: 2019 novel coronavirus disease; BA.5; COVID-19; IgG; Omicron; Portugal; SARS-CoV-2; coronavirus disease; respiratory infections; seroepidemiological survey; seroprevalence; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.