Durability of neutralization against Omicron subvariants after vaccination and breakthrough infection

Booster immunizations and breakthrough infections can elicit severe acute respiratory syndrome coronavi-rus 2 (SARS-CoV-2) Omicron subvariant neutralizing activity. However, the durability of the neutralization response is unknown. We characterize the sensitivity of BA.1, BA.2, BA.2.75, BA.4/BA.5, BF.7, BQ.1.1, and XBB against neutralizing antibodies from vaccination, hybrid immunity, and breakthrough infections 4-6 months after vaccination and infection. We show that a two-dose CoronaVac or a third-dose ZF2001 booster elicits limited neutralization against Omicron subvariants 6 months after vaccination. Hybrid immu-nity as well as Delta, BA.1, and BA.2 breakthrough infections induce long-term persistence of the antibody response, and over 70% of sera neutralize BA.1, BA.2, BA.4/BA.5, and BF.7. However, BQ.1.1 and XBB, followed by BA.2.75, are more resistant to neutralization, with neutralizing titer reductions of -9-to 41-fold, -16-to 63-fold, and -4-to 25-fold, respectively. These data highlight additional vaccination in CoronaVac-or ZF2001-vaccinated individuals and provide insight into the durability of neutralization against Omicron subvariants.

Automated summary

A study found that the durability of neutralizing antibodies against the Omicron subvariants is uncertain 4-6 months after vaccination or infection. Two doses of CoronaVac or a third dose of ZF2001 produce limited neutralization against Omicron subvariants 6 months after vaccination. Hybrid immunity and Delta, BA.1, and BA.2 breakthrough infections induce long-term persistence of the antibody response, with over 70% of sera neutralizing BA.1, BA.2, BA.4/BA.5, and BF.7. However, BQ.1.1 and XBB, as well as BA.2.75, show higher resistance to neutralization. These data suggest the need for additional vaccination in CoronaVac or ZF2001-vaccinated individuals and provide insight into the durability of neutralization against Omicron subvariants.