Fig. 1.

PRNT₅₀ antibody titres to wild-type (WT) SARS-CoV-2 and Omicron subvariants BA.1, BA.2, BA.2.12.1, BA.4 and BA.5. A: Uninfected BNT162b2 individuals or CoronaVac vaccinated and non-vaccinated convalescent individuals from WT SARS-CoV-2 infection. GMTs to each virus in the same cohort are connected by lines. B: BA.2 infections in vaccinated (n = 17) and unvaccinated individuals (n = 7). GMTs in acute and convalescent stages were connected by lines. Comparison of antibody titres to different viruses was done using the Wilcoxon signed-rank test when comparing paired antibody titres to different viruses in the same serum and the two tailed Mann-Whitney U test when comparisons were made between different groups of individuals. The horizontal dotted line at a titre 1:25.6 represents the 50% protective titre against symptomatic infection and the shaded area represents the 95% confidence interval of this protective threshold (see results and reference [11] for details).