Figure 1.
PRNT50 antibody titres to WT SARS-CoV-2 and Omicron subvariants BA.1 and BA.2, in infection-naïve and previously-infected (by WT virus) individuals, according to Comirnaty or CoronaVac vaccination, Hong Kong, 21 February–20 November 2021 (n = 120)
GMT: geometric mean of neutralising antibody titres; PRNT50 : 50% plaque reduction neutralisation test; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; SD: standard deviation; WT: wild type.
A. PRNT50 antibody titres of each individual are linked by a line. GMTs for each group are indicated above in parentheses. Antibody titres between pairs of viruses were compared using the Wilcoxon signed-rank test.
B. PRNT50 antibody titres to Omicron subvariant BA.2 in the different groups, with geometric mean +/− SD presented for ease of comparison (Table 1 displays the numbers of individuals in each group). The dashed line indicates the predicted threshold of PRNT50 antibody titre (1:25.6) conferring 50% protection from infection, and shading indicates 95% confidence intervals [11,16]. Mann–Whitney test (two tailed) was used for significance testing. Exact p values are denoted.
