AS01

backgroundThe AS01

methodsWe conducted a review of post-marketing safety surveillance data following adjuvanted RSVPreF3 administration. Spontaneous adverse events (AEs) that were reported worldwide since the first approval (3 May, 2023) to 2 May, 2025 in the GSK global safety database were analyzed.

resultsUp to 2 May, 2025, 13.4 million doses of adjuvanted RSVPreF3 were distributed globally. A total of 2861 spontaneous reports, including 7012 AEs (serious: 11.0%), were received. The most frequent AEs consisted mainly of non-serious reactogenic events. Of all reports, 1164 described vaccination errors, with most frequent errors consisting of either wrong product administration (N = 243) or administration to patients of an inappropriate age (N = 204). The majority (90.3%) of vaccination error reports were not associated with any other AEs. Adjuvanted RSVPreF3 was erroneously administered to pregnant individuals in 415 cases; most reports (95.2%) occurred without associated AEs. Observed-to-expected analysis of reports of Guillain-Barré syndrome (N = 37) did not suggest an increased risk compared to background incidence of this event and the reports of atrial fibrillation (N = 29) did not indicate an excess risk.

conclusionsReview of the post-marketing surveillance data from 2 years of exposure to adjuvanted RSVPreF3 showed that the safety profile of the vaccine is consistent with that observed in clinical trials supporting an unchanged and favorable benefit-risk profile for the vaccine. Additional post-marketing surveillance is ongoing to further evaluate a potential risk of rare AEs, such as Guillain-Barré syndrome, following adjuvanted RSVPreF3 vaccination.