An XBB.1.5-based inactivated SARS-CoV-2 vaccine partially protects against XBB.1.5 and JN.1 strains in hamsters

The SARS-CoV-2 Omicron BA.2.86 variant and its descendant lineages, including JN.1, are rapidly spreading and becoming dominant globally. Vaccination is an essential primary preventative measure. While mRNA vaccines have been widely used worldwide, it is essential that we continue to prepare alternative vaccine modalities. Consistent with WHO recommendations, we developed an inactivated Omicron XBB.1.5 vaccine and assessed its efficacy against XBB.1.5 and JN.1 strains. Immunization with the inactivated XBB.1.5 vaccine induced antigen-specific antibodies leading to protection from XBB.1.5 and antigenically distinct JN.1 strains in a hamster model. In addition, we found that immunization reduced viral replication in hamster respiratory organs, suggesting protection against XBB.1.5 and JN.1 variants. Our findings highlight the potential of inactivated vaccines against evolving SARS-CoV-2 variants.