Alves, K., et al. Immunogenicity and safety of a monovalent omicron XBB.1.5 SARS-CoV-2 recombinant spike protein vaccine as a heterologous booster dose in US adults: interim analysis of a single-arm phase 2/3 study.

Alves, K., et al. Immunogenicity and safety of a monovalent omicron XBB.1.5 SARS-CoV-2 recombinant spike protein vaccine as a heterologous booster dose in US adults: interim analysis of a single-arm phase 2/3 study.

Lancet Infect Dis, 2025 May, 25(5):585-594. PMID: 39824198

• This study evaluates the immunogenicity and safety of NVX-CoV2601, a monovalent protein-based COVID-19 vaccine (Novavax) targeting the Omicron XBB.1.5 variant, in adults previously vaccinated with multiple mRNA doses. The NVX-CoV2601 vaccine was adjuvanted with Matrix-M, a saponin-based adjuvant designed to enhance immune responses.
• Results showed that a single dose of NVX-CoV2601 elicited superior neutralizing antibody responses against XBB.1.5 and other circulating variants compared to a historical control group receiving the prototype vaccine, with a favorable safety profile consistent with prior studies. The vaccine was well tolerated, with few adverse events and no safety signals of concern, supporting its potential as an effective booster to enhance immunity against emerging SARS-CoV-2 variants.

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