Table 1.  SARS-CoV-2 Neutralizing Antibodies in Tested Plasma Pools
Week in 2020
Parameter  13  14  15  16  20  24  28
Plasma pools ≥LOD, %  0.0  1.3  1.3  6.3  0.0  5.0  7.0
µNT50 of plasma pool titers ≥LOD, 1:X  n.a.  37  5  6, 18, 26, 34, 87  n.a.  7, 10, 20, 22  4, 7, 8, 9, 12, 18, 24
Number of plasma pools tested  40  80  80  80  100  80  100
SARS-CoV-2 nAb positive plasma donors in Austria, %  0.00  0.21  0.21  1.04  0.00  0.83  1.17
Cumulative COVID-19 incidence in Austria, %a  0.10  0.14  0.16  0.17  0.18  0.19  0.21
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.