An omicron-based vaccine booster elicits potent neutralizing antibodies against emerging SARS-CoV-2 variants in adults

ABSTRACT

SARS-CoV-2 Omicron subvariants have become the predominantly strain in most countries. However, the neutralizing activity of the human serum after Omicron-based vaccine booster against different SARS-CoV-2 variants is poorly understood. Here, we developed an update Omicron vaccine (SCoK-Omicron), based on the RBD-Fc fusion protein vaccine (SCoK) and RBD domain of Omicron BA.1. To assess cross-variant neutralizing activity in adults, 25 volunteers that have received three doses of SCoK and 25 volunteers with two doses of CoronaVac (inactive vaccine) were further boosted with a dose updated vaccine (SCoK-Omicron). The results of pseudovirus neutralization assays demonstrated that the booster potently induced the high-level of neutralizing antibody against SARS-CoV-2 Wild type, Delta and Omicron subvariants in adults. Further assays of single point mutations showed that K444T, L452R, N460K, or F486V was key mutations to cause immune evasion. Together, these data suggest that SCOK-Omicron can be used as a booster vaccine candidate in adults receiving subunit protein or inactivated vaccine in response to the epidemic of COVID-19 Omicron subvariants, and the mutation K444T, L452R, N460K, or F486V needs to be considered in future vaccine design.

KEYWORDS:

• SARS-CoV-2
• Omicron
• vaccine
• booster
• neutralizing titers

Acknowledgements

The authors wish to thank Yong Zhang, Shuangli Zhu and Dongmei Yan (National Institute for Viral disease and Prevention, Chinese Center for Disease Control and Prevention) for the experiments about live virus.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data are available in this article, supplementary materials, or available from the corresponding authors.

Additional information

Funding

This work is funded by Supported by Beijing Natural Science Foundation (M23001), National Program on Key Research Project of China (2020YFC0860100), and the State Key Laboratory of Pathogen and Biosecurity (Academy of Military Medical Science, SKLPBS2106).