Respiratory Syncytial Virus Vaccination Is Associated With Increased Odds of Preterm Birth.
Ilari Kuitunen, Marjut Haapanen
✦ AI-curated · Sources linked
In 30 seconds
This rapid review and meta-analysis assessed whether RSV vaccination during pregnancy was associated with preterm birth, defined as birth before 37 gestational weeks. It included six randomised controlled trials (17 656 births) and two observational studies (3446 births). Pooled results showed increased odds of preterm birth overall (OR 1.13, CI 1.00-1.27), with moderate certainty of evidence. The association was present in the randomised studies (OR 1.17, CI 1.02-1.34), whereas observational studies showed no evidence of a difference (OR 0.93, CI 0.69-1.25).
Key findings
- Across study designs, pooled odds of preterm birth were increased (OR 1.13, CI 1.00-1.27).
- Randomised trials showed increased odds (OR 1.17, CI 1.02-1.34); observational studies showed no evidence of a difference (OR 0.93, CI 0.69-1.25).
- For market-approved vaccine in randomised trials, odds seemed increased (OR 1.21, CI 0.98-1.49).
- Evidence certainty was rated moderate.
Why it matters
The findings identify a possible perinatal safety signal relevant to maternal RSV vaccination, while the differing results across randomised and observational evidence leave the magnitude and interpretation uncertain. Continued population-level monitoring during early vaccine rollouts can help assess preterm birth outcomes and clarify whether the observed association is confirmed.
What to keep in mind
The pooled estimate combines randomised and observational studies, which gave differing results. The market-approved-vaccine estimate had a confidence interval spanning no difference.