Maternal vaccination protects infants from RSV
Vaccinating pregnant people against respiratory syncytial virus reduced infant infections and severe illness without clear safety harms.
*Systematic review and meta-analysis of phase 3 randomized trials; Level 1a (OCEBM).

Citation

Torres-Torres J, Rojas-Zepeda L, Villafan-Bernal JR, et al. Maternal RSV vaccination for infant protection: A systematic review and meta-analysis of phase 3 trials with an integrated economic evaluation. International Journal of Gynecology & Obstetrics. 2026;173:63–73. doi:10.1002/ijgo.70641.

Background

Respiratory syncytial virus (RSV) is a major cause of serious lung infection in early infancy. Vaccinating during pregnancy may protect infants, but safety concerns and cost questions have limited uptake.

Patients

Healthy pregnant women aged 18–49 years with singleton, low-risk pregnancies in phase 3 randomized trials; generally excluded non-randomized studies and reports without extractable data.

Intervention

Maternal RSV vaccination during late pregnancy (about 31–32 weeks).

Control

Placebo.

Outcome

Infant laboratory-confirmed RSV infection and severe RSV illness; maternal and pregnancy safety outcomes; modeled health and cost impact for Mexico.

Follow-up Period

Infant outcomes assessed through 90–180 days; trial follow-up up to 6–12 months.

Results

Four phase 3 trials (17,391 participants) were included.
Infant outcome (first 90–180 days) Relative effect Number needed to vaccinate
Any RSV infection (primary) Risk ratio 0.47 (95% confidence interval 0.29–0.76) 85
Severe RSV illness Risk ratio 0.36 (95% confidence interval 0.21–0.60) 127
RSV = respiratory syncytial virus.
No clear increases were seen for preterm birth, pre-eclampsia, or stillbirth.
In a Mexico model, vaccinating the annual birth cohort at a list price of about US$295 per dose was costly per event prevented; at about US$50 per dose, cost-effectiveness improved markedly.

Limitations

Only four trials were available, and definitions/timing for “any RSV infection” differed across studies. The cost model was simplified and excluded indirect savings (for example, fewer hospital stays) and long-term benefits; results depend strongly on vaccine price and local RSV death rates.

Funding

Institutional support from Mexico’s National Perinatology Institute; publication charges only.

Clinical Application

Offer maternal RSV vaccination to reduce infant RSV illness; prioritize implementation where RSV burden is high and negotiated public-sector pricing makes programs affordable.