Understanding the Risks of RSV Vaccine

While not downplaying the serious nature of respiratory syncytial virus (RSV) in compromised individuals, knowing the risks of the RSV vaccine can help you make an informed decision.

RSV in Infants

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTI) in infants worldwide. However, mortality rates are very low. 97% of infant deaths occur in underserved populations where nutrition, living conditions, hygiene, and healthcare availability are insufficient. (1)

CDC Recommendation

The CDC recommends the RSV vaccine ABRYSVO for pregnant women. (2)

Vaccine Information

"ABRYSVO has not been evaluated for the potential to cause carcinogenicity, genotoxicity, or impairment of male fertility.
It is not known whether ABRYSVO is excreted in human milk. Data are not available to assess the effects of ABRYSVO on the breastfed infant or on milk production/excretion.
The results of a post-marketing observational study suggest an increased risk of Guillain-Barré syndrome during the 42 days following vaccination with ABRYSVO."

FDA Press Release (2023)

A press release from the FDA approving ABRYSVO noted that in safety studies, low birth weight and jaundice in infants occurred at a higher rate in pregnant ABRYSVO recipients compared to pregnant placebo recipients. (4)

"Preterm births in ABRYSVO recipients (5.7%) occurred compared to those who received placebo (4.7%). The available data are insufficient to establish or exclude a causal relationship between preterm birth and ABRYSVO. To avoid the potential risk of preterm birth, administer ABRYSVO as indicated at 32 through 36 weeks of gestational age."

Facts

• Infants whose mothers contracted RSV during pregnancy were found to have maternal antibodies. Antibodies decline over time but remain present for about six months. (5)
• Breastfeeding after RSV infection provides antibodies to the infant, offering protection during immune system development. (6)

ABRYSVO Ingredients

The vaccine contains DNA, residual host cell proteins, and two stabilizers worth noting:

• Tromethamine hydrochloride: FDA Category C - Unknown if it will harm an unborn baby. (8)
• Polysorbate 80: Evidence suggests maternal intake can promote metabolic syndrome in offspring and impair microbiome development. (9)

Making an Informed Decision

Being armed with facts will better equip you to make the right choice for yourself and your unborn child.

References

1. Munro APS, et al. (2023). The disease burden of respiratory syncytial virus in Infants. Curr Opin Infect Dis. Link
2. Centers for Disease Control and Prevention. (2024). Protect Your Baby From RSV
3. Pfizer Laboratories Div Pfizer Inc. (2025). ABRYSVO Information
4. FDA. (2023). FDA Press Release
5. Cox KR, et al. (2023). RSV infection in pregnant patients. AJOG Glob Rep. Link
6. Anderson EJ, Doffinger R. (2024). Role of antibody-mediated immunity in protecting children from RSV. Link
7. Pfizer Medical Information. ABRYSVO Description
8. Kaiser Permanente. Tromethamine
9. iran Liang et al. (2024). Maternal polysorbate 80 intake study. Link

Written By Brooke Lounsbury