Ad26.RSV-B.preF2

Ad26.RSV-B.preF2 is an investigational adenovirus serotype 26 (Ad26) vector-based vaccine candidate developed by Janssen Vaccines & Prevention B.V. (a Johnson & Johnson company) for the prevention of respiratory syncytial virus (RSV) infection. It encodes a prefusion conformation-stabilized RSV fusion protein (preF) derived specifically from the RSV B subtype. This distinguishes it from earlier candidates like Ad26.RSV.preF, which were based on the RSV A subtype. The vaccine is designed to elicit both humoral and cellular immune responses against circulating RSV B strains. It has been evaluated in Phase 1/2a clinical trials (e.g., NCT05327816) in adults aged 60 years and older, both as a standalone component and in various combinations with other RSV vaccine candidates to provide broader protection. In 2023, Johnson & Johnson announced its decision to discontinue its adult RSV vaccine program, which likely includes this candidate.