Serosurveillance of SARS-CoV-2 in Welsh Blood Donors: Establishment of the surveillance system and results up to November 2022.

BackgroundIn 2020, Wales experienced some of the highest rates of confirmed COVID-19 cases in Europe. We set up a serosurveillance scheme using residual samples from blood donations to inform the pandemic response in Wales.AimTo identify changes in SARS-CoV-2 antibody seroprevalence in Wales by time, demography and location.