Immunogenicity and Safety of Coadministration of AS01E-Adjuvanted Respiratory Syncytial Virus Prefusion F Protein Vaccine and a COVID-19 mRNA Vaccine in Adult s Aged ≥50 Years: A Phase 3, Randomized, Noninferiority Trial.
Marc Bonten, Brandon Essink, Nikita Hanning et al.
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In 30 seconds
This phase 3, open-label, multicenter randomized noninferiority trial compared coadministration of an AS01E-adjuvanted RSV prefusion F vaccine and an Omicron XBB.1.5 COVID-19 mRNA vaccine with administration approximately 1 month apart in adults aged ≥50 years. Among 833 vaccinated participants, noninferiority criteria were met for RSV-A and RSV-B neutralizing responses, but narrowly missed for SARS-CoV-2: the Control/Co-Ad GMT ratio was 1.31 (95% CI: 1.13-1.51), exceeding the prespecified upper limit of 1.50. Safety findings were generally balanced, and the authors considered the SARS-CoV-2 result unlikely to indicate clinically relevant interference.
Key findings
- Noninferiority was met for RSV-A (GMT ratio: 1.12 [95% CI: .97-1.28]) and RSV-B (GMT ratio: 1.08 [95% CI: .94-1.23]).
- For SARS-CoV-2 Omicron XBB.1.5, the GMT ratio was 1.31 [95% CI: 1.13-1.51], marginally missing the noninferiority criterion.
- Administration-site pain, myalgia, and fatigue were the most frequently reported solicited events; most were mild to moderate and lasted a median of ≤3 days.
- Unsolicited and serious adverse events were generally balanced between coadministration and sequential-administration groups.
Why it matters
Coadministration may allow adults aged ≥50 years to receive RSV and COVID-19 vaccines together, with less need for separate vaccination visits. The trial found comparable RSV immune responses and generally balanced safety findings, while the SARS-CoV-2 noninferiority threshold was narrowly missed. This distinction helps clinicians interpret the evidence without treating the immune-response result as proof of clinically meaningful interference.
What to keep in mind
The trial assessed neutralizing antibody responses at 1 month; the abstract does not report clinical protection outcomes.