AS01E-Adjuvanted Respiratory Syncytial Virus Prefusion F Protein Vaccine (Adjuvanted RSVPreF3): Review of the First 2 Years of Post-Marketing Safety Surveillance

The AS01E-adjuvanted respiratory syncytial virus prefusion F protein vaccine (adjuvanted RSVPreF3) received its first marketing authorization in May 2023 for the prevention of respiratory syncytial virus lower respiratory tract disease in individuals aged ≥ 60 years. We 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. Up 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. Review 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. Respiratory syncytial virus is an important cause of severe lung infections in older adults. Adjuvanted RSVPreF3 vaccine was first approved in 2023 to prevent respiratory syncytial virus disease in adults aged 60 years and older. Regularly analyzing safety information from ongoing studies and real-world data (from routine healthcare practice) is essential to identify any potential new risks linked to adjuvanted RSVPreF3. Using the manufacturer’s (GSK) safety database, we analyzed the real-world safety data from individuals who experienced adverse events after vaccination with adjuvanted RSVPreF3. These data were collected during the first 2 years since the vaccine’s initial approval. The majority of adverse events reported to the manufacturer were mild and consistent with those reported in clinical trials. Most individuals who received the vaccine by mistake did not experience adverse events. The proportion of individuals who experienced Guillain–Barré syndrome after vaccination was within the range of background incidence rates of this disease in older adults. The reports of atrial fibrillation reflected the natural history of the disease for the older population. The safety data, collected over 2 years of substantial exposure to adjuvanted RSVPreF3, show that the safety profile of this vaccine is similar to that seen in clinical trials. Together with pre-licensure data demonstrating the vaccine’s ability to protect and help the immune system against respiratory syncytial virus disease, and real-world data demonstrating that adjuvanted RSVPreF3 protects against respiratory syncytial virus-associated hospitalization, the safety information collected so far supports the vaccine’s use for the people for whom it is authorized.