Immunogenicity and Safety of the Adjuvanted Respiratory Syncytial Virus Prefusion F Protein-Based Vaccine When Co-administered With the Adjuvanted Recombinant Herpes Zoster Subunit Vaccine in Adults ≥ 50 Years of Age.

In 30 seconds

This phase III, open-label, randomised trial compared co-administration of adjuvanted RSVPreF3 and recombinant zoster vaccine (RZV) with administration one month apart in adults aged ≥50 years. Among 530 participants, immune responses met the prespecified non-inferiority criteria: the Control/Co-Ad geometric mean titer ratios were 1.1 (95% CI = 1.0-1.4) for RSV-A and 1.0 (0.8-1.2) for RSV-B; the anti-gE antibody concentration ratio was 1.2 (1.1-1.4). Solicited adverse events were more frequent after co-administration than after either vaccine given separately, while no fatal or related serious adverse events were reported.

Key findings

• RSV-A and RSV-B neutralizing antibody responses met non-inferiority criteria, with Control/Co-Ad ratios of 1.1 (95% CI = 1.0-1.4) and 1.0 (0.8-1.2), respectively.
• The anti-gE antibody concentration ratio was 1.2 (1.1-1.4), meeting the prespecified non-inferiority criterion.
• Solicited systemic adverse events after visit 1 occurred in 73.6% of co-administration participants and 60.4% of controls; grade 3 events occurred in 9.3% and 6.2%, respectively.
• No fatal or related serious adverse events were reported.

Why it matters

Adults aged 50 years and older may be eligible for both RSV and zoster vaccination. These trial results indicate that giving the vaccines together preserved measured immune responses compared with spacing them one month apart, while solicited reactions were common and more frequent with co-administration. The findings inform discussion of a combined visit without implying that reactogenicity is unchanged.

What to keep in mind

The trial was open-label, and the abstract reports immunogenicity and safety outcomes rather than clinical protection against RSV or herpes zoster.