Abbreviations: µNT50, neutralization titer for 50% of the wells; COVID-19, coronavirus disease 2019; LOD, limit of detection; n.a., not applicable; nAb, neutralizing antibody; PCR, polymerase chain reaction; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
aSARS-CoV-2 PCR-positive individuals per 100 000 population in Austria are described as cumulative COVID-19 incidence in percent.