Respiratory Syncytial Virus Vaccination Is Associated With Increased Odds of Preterm Birth.

Summary

This rapid review/meta-analysis found a modest but statistically significant increase in the odds of preterm birth in RCTs of maternal RSV vaccination (OR 1.17), with overall pooled OR 1.13 across RCTs and observational studies. The findings warrant active perinatal safety surveillance during early vaccine rollouts.

Key Findings

• In RCTs (n=17,656 births), maternal RSV vaccination increased preterm birth odds (OR 1.17, 95% CI 1.02–1.34).
• Observational studies (n=3,446) showed no significant difference (OR 0.93, 95% CI 0.69–1.25).
• Overall pooled analysis indicated increased odds (OR 1.13, 95% CI 1.00–1.27) with moderate certainty (GRADE).
• Market-approved vaccine subset in RCTs showed a trend toward increased odds (OR 1.21, 95% CI 0.98–1.49).

Clinical Implications

Clinicians should counsel pregnant patients with up-to-date evidence, and health systems should implement robust perinatal pharmacovigilance to quantify risk and guide recommendations as more data accrue.

Limitations

• Rapid review design; potential heterogeneity and residual confounding across studies.
• Fixed-effects model may not fully capture between-study variance; limited power in vaccine-specific subgroup.

Future Directions

Expand population-based active safety surveillance; conduct mechanistic and subgroup analyses (e.g., gestational age at vaccination, comorbidities); update meta-analyses as new RCT and real-world data emerge.