Respiratory syncytial virus (RSV) is not just for toddlers. Responsible for bronchiolitis and pneumonia, it also threatens the elderly, especially as winter approaches. A new study confirms the effectiveness of the RSV vaccine in seniors… over two consecutive seasons.
A virus to watch closely
Long unknown to the general public, RSV has made headlines again since the arrival of effective vaccines for both infants and seniors. If vaccination is in fact not compulsory, it is now recommended for babies but also for people aged 75 and over, as well as from 65 years of age for those with chronic heart or respiratory diseases.
“RSV can cause bronchiolitis or pneumonia, particularly in infants and the elderly. This is why vaccination is recommended for these age groups”recalls Dr. Gérald Kierzek, emergency physician and medical director of True Medical.
One dose, two winters of protection
Good news for those who fear injections: according to a study published on August 30, 2025 in the journal JAMAa single injection of the RSV vaccine is enough to protect seniors for two winter seasons, or approximately two years.
Researchers from the American Centers for Disease Control and Prevention (CDC) analyzed data from 6,958 people aged 60 and over, hospitalized for an acute respiratory illness in 26 hospitals across 20 states, between October 2023 and April 2025.
Result :
- A risk of hospitalization reduced by 69% the first year after vaccination;
- An efficiency still of 48% the second year, or 58% over two seasons in total.
In other words, even without an annual booster, the vaccine continues to effectively protect seniors against serious forms linked to RSV.
“Clearly positive” results
“These results clearly demonstrate that RSV vaccines prevent hospitalizations and serious illness from infection in older adults,” praised Dr. Wesley Self, co-author of the study. “It is encouraging to see the benefits of this new vaccination program for public health.”
The study also highlights that protection is particularly strong among those over 75 (68% effective) and among non-immunocompromised people. However, it remains lower (around 30%) in patients whose immune systems are weakened.
Is there a need for a reminder every year?
The question remains open. The authors note that vaccine effectiveness tends to decrease over time. “Re-administering the vaccine at regular intervals could be a strategy to consider to maintain protection”, they say.
In France, the High Authority of Health (HAS) remains cautious. In its recommendations of July 4, 2024, it indicated that it did not comment on “on the relevance and necessity of iterative vaccination” as long as the data on the duration of protection was not sufficient.
For Dr Gérald Kierzek, nothing currently justifies an annual recall:
“This study is in the direction of prolonged protection after a single dose. It will still be necessary to evaluate, with hindsight, the real duration of this protection to know when to consider a booster vaccination.”
One more step towards respiratory prevention
After the Covid-19 pandemic and flu vaccination campaigns, RSV prevention is now emerging as a new pillar of winter public health. Three vaccines are currently available for seniors: Arexvy® (GSK), Abrysvo® (Pfizer) and mResvia® (Moderna). All have demonstrated notable effectiveness in reducing severe forms and hospitalizations.
Not to be confused with the injection for infants. For them, it is not a classic vaccine, but an injection of monoclonal antibody (Beyfortus®), administered at birth or before winter, in order to avoid severe bronchiolitis. So that everyone is well protected.
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The RSV vaccine protects seniors for two seasons, with 69% effectiveness the first year and 48% the following.
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Vaccination is recommended from age 75, and from age 65 for people at risk.
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No annual booster planned at this time, but continued monitoring of data could adjust recommendations.
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RSV remains a potentially serious respiratory virus, preventable through vaccination.