RSV vaccines safe and effective, Cochrane review finds

The review demonstrates that vaccines for respiratory syncytial virus (RSV) are both safe and effective in protecting groups who are most at risk for serious illness, including older adults and infants.  

RSV is a common virus that causes coughs and colds but can also lead to life-threatening lung infections like pneumonia. Children under the age of two months are at the highest risk of severe RSV infection and death, with older adults also vulnerable to severe disease.  

An international group of researchers analysed 14 clinical trials with over 100 000 participants, including older adults, pregnant people, women of childbearing age, and children. Trials were conducted across a wide range of countries, spanning all continents. 

Protection for older adults and benefits for infants
Results showed strong evidence that the RSV prefusion vaccines in older adults reduce RSV-associated lower respiratory tract disease such as pneumonia and bronchitis by 77% and RSV-associated acute respiratory disease (e.g. a cold) by 67%.

Vaccination of pregnant people with an RSV F protein-based vaccine reduced the risk of their children needing medical care for RSV-associated lower respiratory tract disease by 54%, reduced the babies’ chance of severe RSV-related disease by 74%, and lowered the risk of hospitalisation by 54%.   

“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,” said Dr. KM Saif-Ur-Rahman, lead author and Senior Research Methodologist at Evidence Synthesis Ireland and Cochrane Ireland, University of Galway, Ireland. “That is encouraging news for two of the groups most at risk.”  

The review found little to no difference in serious side effects across all age groups between groups who are vaccinated and groups who are not vaccinated.  

The findings of this review are based on clinical trial data, as real-world evidence on effectiveness and safety was not yet available at the time of publication.  

“It’s important to be clear that our review is based on evidence from randomised trials, the strongest evidence available,” said Kate Olsson, author and ECDC vaccine expert. “Post authorisation, 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.”  

The systematic review is planned to be complemented by two additional analyses on the efficacy, effectiveness, and safety of different RSV vaccines following search updates. ECDC plans to publish the first update with new data in the coming weeks.

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Notes to editors:  

[1] ‘Efficacy and safety of respiratory syncytial virus vaccines’ is published in the Cochrane Database of Systematic Reviews. Available from: https://doi.org/10.1002/14651858.CD016131   The review was commissioned and supported by the European Commission and the European Health and Digital Executive Agency on behalf of the European Centre for Disease Prevention and Control (ECDC).  

[2] RSV prefusion vaccines are a newer type of vaccine that target a specific form of the RSV's surface protein (F protein) to prompt a person's immune system to respond against the virus. With this immune response the aim is to prevent severe lower respiratory tract disease.

[3] Vaccine efficacy is the degree to which a vaccine lowers the risk of getting the disease, under ideal and controlled circumstances in a clinical trial.
Vaccine effectiveness is the degree to which a vaccine lowers the risk of getting the disease in a population once the vaccine is used in real-life conditions. Effectiveness in the real world can differ from the efficacy measured in a clinical trial.