Publication date: Jul 17, 2023
The SARS-CoV-2 Omicron subvariant BA. 5 rapidly spread worldwide and replaced BA. 1/BA. 2 in many countries, becoming globally dominant. BA. 5 has unique amino acid substitutions in the spike protein that both mediate immune escape from neutralizing antibodies produced by immunizations and increase ACE2 receptor binding affinity. In a comprehensive, long-term (up to 9 months post primary vaccination), experimental vaccination study using male Syrian hamsters, we evaluate neutralizing antibody responses and efficacy against BA. 5 challenge after primary vaccination with Ad26. COV2. S (Janssen) or BNT162b2 (Pfizer/BioNTech) followed by a homologous or heterologous booster with mRNA-1273 (Moderna) or NVX-CoV2373 (Novavax). Notably, one high or low dose of Ad26. COV2. S provides more durable immunity than two primary doses of BNT162b2, and the NVX-CoV2373 booster provides the strongest augmentation of immunity, reduction in BA. 5 viral replication, and disease. Our data demonstrate the immunogenicity and efficacy of different prime/boost vaccine regimens against BA. 5 infection in an immune-competent model and provide new insights regarding COVID-19 vaccine strategies.
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|disease||MESH||Emerging Infectious Diseases|