No, Both Are NOT Fine for Pregnancy
Only Abrysvo (Pfizer RSVpreF) is FDA-approved and recommended for use during pregnancy; Arexvy (GSK) is NOT approved for pregnancy and should not be used in pregnant individuals. 1, 2
Clear Distinction Between the Two Vaccines
Abrysvo (Pfizer) - APPROVED for Pregnancy
- FDA-approved in August 2023 specifically for pregnant persons at 32-36 weeks' gestation 1, 2
- ACIP/CDC recommended in September 2023 for seasonal administration (September through January) during weeks 32-36 of pregnancy 2
- Designed to prevent RSV-associated lower respiratory tract disease in infants <6 months of age through maternal antibody transfer 2
Arexvy (GSK) - NOT APPROVED for Pregnancy
- Only approved for adults ≥50-60 years of age 3, 4
- No pregnancy indication in FDA labeling
- Post-marketing surveillance data shows inappropriate off-label use during pregnancy, with 6.6% (n=375) of Arexvy reports involving pregnancy exposure despite lack of approval 5
- This represents a vaccine administration error and highlights gaps in healthcare provider education 5
Important Safety Considerations for Abrysvo in Pregnancy
While Abrysvo is approved, there are critical safety signals to understand:
Preterm Birth Signal
- Clinical trials showed numerical imbalance in preterm births (<37 weeks) in vaccine recipients versus placebo, though differences were not statistically significant 2, 1
- Meta-analysis suggests preterm delivery may be more likely (RR 1.24 [1.08,1.44]; P=0.003), though evidence certainty is very low 6, 7
- FDA restricted approval to 32-36 weeks' gestation specifically to avoid potential risk of preterm birth <32 weeks, which carries higher morbidity and mortality 2, 1
Other Maternal Safety Signals
- More hypertensive disorders of pregnancy observed in vaccine recipients (though not statistically significant) 2, 1
- Common adverse reactions include injection site pain (40.6%), headache (31.0%), muscle pain (26.5%), and nausea (20.0%) 1
- Post-marketing data shows preterm birth (11%) and hypertensive disorders (7%) as most reported pregnancy-specific outcomes 8
Reassuring Safety Data
- No effect on congenital abnormalities (RR 0.96,95% CI 0.88-1.04; high-certainty evidence) 6
- Likely no effect on intrauterine growth restriction (moderate-certainty evidence) 6
- May have little or no effect on stillbirth and maternal death (low-certainty evidence) 6
Clinical Algorithm for RSV Prevention in Pregnancy
If patient is 32-36 weeks pregnant during RSV season (September-January):
- Offer Abrysvo only - single 0.5 mL IM dose 1, 2
- Screen for high-risk pregnancy exclusions (BMI >40 kg/m², preeclampsia, uncontrolled hypertension, placental abnormalities, significant bleeding disorders) 1
- Counsel about potential preterm birth signal and benefits of infant RSV protection
- Document that infant will NOT need nirsevimab after birth (one or the other, not both) 2
If patient receives Arexvy by error:
- This is a vaccine administration error requiring reporting 5
- Monitor for adverse pregnancy outcomes
- Counsel patient about off-label use
Bottom Line
The question implies both vaccines are interchangeable for pregnancy - this is categorically false and potentially dangerous. Only Abrysvo has undergone pregnancy-specific trials, received FDA approval for maternal use, and has ACIP/CDC recommendations for administration during pregnancy. Using Arexvy in pregnancy represents inappropriate off-label use that has been documented as a recurring administration error in post-marketing surveillance 5, 9.