RSV Vaccine Safety: Older Adults & Pregnant Patients

Respiratory syncytial virus (RSV) infections pose a significant health risk for older adults and children younger than 6 months of age. Serious cases may require hospitalization, and 10,000 to 23,000 deaths occur each year in the United States due to RSV.¹

In May 2023, the FDA approved 2 vaccines, Arexvy (GSK) and Abrysvo (Pfizer), to prevent lower respiratory tract disease caused by RSV in individuals 60 years of age and older. Abrysvo received FDA approval in August 2023 for use in pregnant patients during gestational weeks 32 to 36 to protect infants from birth through 6 months.² Arexvy is not approved for use in pregnancy due to an increased risk of preterm delivery during phase 3 clinical trials.³

Study findings published in Preventive Medicine Reports examined the safety of the RSV vaccines after FDA approval for use in older adults and pregnancy. Investigators evaluated Vaccine Adverse Event Reporting System (VAERS) data from May 3, 2023, to December 27, 2024, to assess safety as determined by adverse reactions.²

During this timeframe, 6790 VAERS events were reported in the US, with 521 events categorized as serious and 6269 as non-serious. The most common serious adverse event was Guillain-Barré syndrome (GBS), and the most common non-serious adverse event was injection site reaction. Other adverse reactions included 19 occurrences of anaphylaxis and 14 occurrences of cellulitis.²

More than half of the patients who were vaccinated during pregnancy did not experience an adverse event. The most common adverse event during pregnancy was preterm delivery. The authors also observed that even though Arexvy is not approved for use during pregnancy, it was inappropriately administered to 367 pregnant patients.²

The study findings support previous data suggesting that the majority of RSV vaccine adverse reactions are non-serious. The prevalence of preterm delivery and GBS warrants additional monitoring, as does administration of the proper product during pregnancy.¹

REFERENCES

1. Surveillance of RSV. CDC. Updated July 8, 2025. Accessed August 13, 2025. https://www.cdc.gov/rsv/php/surveillance/index.html

2. Junchao L,Zhiyuan Z, Meixiang W. Post-licensure safety of respiratory syncytial virus vaccines, Vaccine Adverse Event Reporting System, United States, May 2023–December 2024. Preventive Medicine Reports. 2025;56:103150.

3. Patel D, Chawla J, Blavo C. Use of the Abrysvo Vaccine in Pregnancy to Prevent Respiratory Syncytial Virus in Infants: A Review. Cureans. 2024; 16 (8): E68349. two: 10.7759/Cureus.68349