RSV vaccine in pregnancy: a small gestational hypertension signal, not pre-eclampsia

Design

Systematic review and meta-analysis of 3 RCTs and 6 retrospective cohorts

Population

148,267 pregnant people, RSVpreF vs unvaccinated or placebo

Primary outcome

Hypertensive disorders of pregnancy

Effect

RR 1.08 (95% CI 1.02–1.13), I² 44%; RCTs alone RR 1.12 (0.87–1.43)

A systematic review and meta-analysis, published in August, pooled nine studies of the bivalent RSV prefusion F vaccine (RSVpreF) given in pregnancy — three randomised trials and six retrospective cohorts, 148,267 pregnancies in all. The question came from the pivotal phase 3 trial, which had shown a numerical but non-significant imbalance in hypertensive disorders.

Overall, vaccination was associated with a small rise in hypertensive disorders of pregnancy (RR 1.08, 95% CI 1.02 to 1.13). That signal came from the observational studies; the randomised trials pointed the same way but were not significant (RR 1.12, 0.87 to 1.43). The excess was in gestational hypertension. There was no significant association with pre-eclampsia or eclampsia.

This supports continuing to offer the vaccine, with the hypertension question on the table during counselling. It does not support withholding it: infant RSV protection is the larger effect, and the signal sits in the milder diagnosis and in data most open to confounding.

• Keep offering maternal RSV vaccination where it is recommended; this review does not change that.
• Mention the small gestational hypertension signal when counselling, alongside the infant benefit.
• Measure blood pressure at antenatal visits after vaccination as usual; no extra monitoring schedule is supported.
• Note that pre-eclampsia and eclampsia were not increased in the pooled data.
• Check local availability: access to maternal RSVpreF in India is limited and its regulatory position here is unclear.

Why it matters

It gives a number to a question patients already ask, and locates the signal in the milder diagnosis.

Don't overread it

The signal rests on observational studies where confounding remains possible; the randomised trials were not significant.

The statistics, in plain English

A risk ratio of 1.08 means about 8% more hypertensive disorders in relative terms — small. The randomised trials' interval (0.87 to 1.43) includes 1, so on randomised evidence alone there is no proven effect. I² of 61% in the observational group means those studies disagreed noticeably with each other, which weakens confidence in the pooled number.

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