SARS-CoV-2 breakthrough infections following inactivated vaccine vaccination induce few neutralizing antibodies against the currently emerging Omicron XBB variants

Abstract

1. •

   Inactivated vaccine breakthrough infection with ancestral variants induced nearly undetectable nAbs against XBB variants.

2. •

   Inactivated vaccine breakthrough infection with Omicron BA.1 or BA.5 evoked very weak nAbs against XBB variants.

3. •

   BA.5 infection induced higher nAbs against XBB variants than BA.1 infection.

Fig. 1

Serum neutralizing antibodies in individuals induced from previous SARS-CoV-2 infections were assessed to neutralize the current Omicron variants. After the SARS-CoV-2 ancestral (A and B), Delta (C and D), Omicron BA.1 (E and F), or Omicron BA.5 (G) variant infection, the convalescent serum samples were collected and cross-neutralizing antibodies (nAbs) against the Omicron BF.7, BQ.1, BQ.1.1, XBB, XBB.1, and XBB.1.5 were assessed by VSV-based pseudovirus assays, and the cross-nAbs in Omicron BA.1 and BA.5 were compared to each other (H). “I” represented a dose of inactivated vaccine. Each data point represented the PVNT₅₀ value from a serum sample. The geometric mean titers (GMTs) for the 50% pseudovirus neutralization titer (PVNT₅₀) are shown at the top of the plots. The limit of detection was set as 10 and the proportion of persons' number with PVNT₅₀ values above the limit of detection of the total participants was also showed. In (H), Data were presented as geometric mean with 95% confidence interval. Statistical comparisons were performed using the two-tailed Wilcoxon matched-pairs signed-rank test (A–G) and Mann-Whitney U test (H) (ns, not significant, P ​> ​0.05; ∗, P ​≤ ​0.05; ∗∗, P ​≤ ​0.01; ∗∗∗, P ​≤ ​0.001; ∗∗∗∗, P ​≤ ​0.0001). Decreased fold of GMTs and significant labels were included in all figures.

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