Adverse events and vaccine administration errors following RSV vaccination: Findings from the United States VAERS...

Three respiratory syncytial virus (RSV) vaccines are marketed in the U.S. for use in adults aged ≥18 years: Arexvy® (GSK), Abrysvo® (Pfizer), and mRESVIA® (Moderna), with only Abrysvo® approved for use during pregnancy. This study describes post-marketing adverse event (AE) reports after RSV vaccination and detected reporting risk signals of administration-related errors using the U.S. Vaccine Adverse Event Reporting System (VAERS).

We searched the VAERS database for reports of AE following RSV vaccination during January 1, 2023 - December 31, 2025. We assessed the characteristics of these reports and described the most commonly reported AEs by RSV vaccine brand. The top 15 most frequently reported AEs and top 10 most frequently reported vaccine administration errors were examined for Arexvy® and Abrysvo®. Disproportionality analyses (reporting odds ratio) were conducted to detect disproportionate reporting risk signals of vaccine administration errors (SAS version 9.4).

During the study period, VAERS received 8365 AE reports following RSV vaccination; most were after Arexvy® (68.2%) and Abrysvo® (29.9%). The 5 most frequently reported AEs for Arexvy® were extra dose administered (15.0%), injection site pain (12.8%), injection site erythema (11.3%), injection site swelling (9.0%), and pain (9.0%); while for Abrysvo®, they included exposure during pregnancy (10.6%), extra dose administered (9.9%), headache (7.7%), fatigue (7.7%) and injection site pain (7.3%). Although not recommended for use during the study period, 4.2% (n = 244) of reports after Arexvy® vaccination were from individuals <50 years old; 6.6% (n = 375) were exposure during pregnancy. Both Arexvy® and Abrysvo® exhibited significant signals for vaccine administration errors such as extra dose administered and product administered to patient of inappropriate age.

Most AE reports following RSV vaccination were non-serious. The potential misuse of Arexvy® during pregnancy and excess dose for both Arexvy® and Abrysvo® highlight potential gaps in healthcare provider education and vaccine record retrieval.