RSV Vaccines Found Safe and Effective Across High-Risk Groups in Cochrane Review
Vaccines for respiratory syncytial virus were found both safe and effective across 100,000 participants and, critically, for older adults and for infants.
K.M. Saif-Ur-Rahman, PhD
A new Cochrane systematic review confirms that respiratory syncytial virus (RSV) vaccines provide substantial protection for the 2 populations at highest risk of severe disease, older adults and infants born to vaccinated mothers, without increasing serious adverse events.1
Researchers analyzed 14 randomized controlled trials including more than 100,000 participants across diverse regions and populations, including older adults, pregnant individuals, women of childbearing age, and children.1
Among older adults, prefusion RSV vaccines reduced RSV-associated lower respiratory tract illness by 77% (95% CI 0.70–0.83) and acute respiratory illness by 67% (95% CI 0.60–0.73) compared with placebo. In infants, maternal vaccination with an RSV F protein-based vaccine reduced medically attended lower respiratory tract illness by 54% (95% CI 0.28–0.71), severe cases by 74% (95% CI 0.44–0.88), and hospitalizations by 54% (95% CI 0.27–0.71).1
“From our review of clinical trials, we found high-certainty evidence that RSV vaccines protect older adults and strong evidence they benefit infants when mothers are vaccinated during pregnancy. That’s encouraging news for 2 of the groups most at risk,” first author KM Saif-Ur-Rahman, PhD, from Evidence Synthesis Ireland and Cochrane Ireland and the University of Galway, said in a statement.2
"The safety and efficacy profiles of available RSV vaccines, a critical consideration for their integration into public health strategies and clinical practice, remain uncertain," the international group of investigators wrote.1 The primary objective of the review was to assess the benefits and harms of available RSV vaccines against placebo, no intervention, vaccines for other respiratory infections, other RSV vaccines, or monoclonal antibodies "across all human populations."1
The literature search, conducted from January 2000 to April 2024, covered CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and the WHO ICTRP, according to the study. The researchers included both randomized and nonrandomized controlled trials but excluded any studies conducted for dose-finding outcomes and assessment of immunogenicity.1
Saif-Ur-Rahman and colleagues designated the following outcomes for both lower and upper respiratory illness and confirmed by laboratory test, as benefits:
- Frequency of RSV illness
- Hospitalization due to RSV disease
- Mortality from illness caused by RSV
- All-cause mortality
- Admission to an intensive care unit
Assessment of harm included serious adverse events related to vaccination, eg, neurologic disorders such as Guillain-Barré syndrome.1
Safety Supported Across Populations
Across all populations studied, the review found little to no difference in serious adverse events, in mortality from RSV-related illness, or from all-cause mortality between vaccinated and unvaccinated participants (low-certainty evidence), authors wrote. They also noted that the phase 3 trials included in the review showed low risk of bias and that the occasional concern with selection bias in random assignment across the phase 1 and phase 2 studies did not affect their overall evidence, which they described as "robust." 1
Evidence for women of childbearing age and for live-attenuated RSV vaccines in infants and children remains uncertain due to limited trial data.
“It’s important to be clear that our review is based on evidence from randomized trials, the strongest evidence available. Post authorization real-world studies are ongoing and data from those studies will continue to add to what we know about the safety and effectiveness of these RSV vaccines,” Kate Olsson of the European Centre for Disease Prevention and Control, said in the Cochrane statement.2
The review, published in the Cochrane Database of Systematic Reviews, was commissioned and supported by the European Commission and the European Health and Digital Executive Agency on behalf of ECDC.1
References
Saif-Ur-Rahman K, King C, Whelan SO, et al. Efficacy and safety of respiratory syncytial virus vaccines. Cochrane Database of Systematic Reviews. 2025;9( CD016131). doi: 10.1002/14651858.CD016131
RSV vaccines safe and effective, Cochrane review finds. News release. Cochrane. September 29, 2025. Accessed September 29, 2025. https://www.cochrane.org/about-us/news/rsv-vaccines-safe-and-effective-cochrane-review-finds
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