RSV Vaccine Protection Waned Within Two Seasons
A study of veterans found vaccine effectiveness against RSV fell over 18 months, particularly for immunocompromised adults.
Updated on Sept. 24, 2026 in Asthma
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A large-scale analysis of 288,111 veterans found that protection against respiratory syncytial virus (RSV) declined significantly between the initial vaccination and an 18-month follow-up. These findings provide critical context for older adults and those with compromised immune systems as they consider their seasonal health management.
Why it matters
Understanding how immunity wanes helps identify when protection against severe respiratory complications may diminish. This data highlights the need for ongoing discussions with physicians regarding long-term prevention strategies, especially for populations at the highest risk.
In a study of 288,111 veterans with a median age of 76.1 years, researchers tracked vaccine effectiveness over 18 months. Effectiveness against RSV-related hospitalizations dropped from 88.9% to 57.3% during the study period.
The players
VA Portland Health Care System
A Department of Veterans Affairs facility that provided the clinical setting for the research.
Oregon Health & Science University
A public research university that collaborated on this investigation into RSV vaccine durability.
The details
The analysis compared vaccinated veterans against unvaccinated controls to estimate the durability of the vaccine's protective immune response. Results showed a consistent decline in efficacy across multiple health outcomes, including emergency department visits and intensive care admissions. The decline was most pronounced among immunocompromised patients, who experienced a sharper reduction in immunity over the 18-month timeframe compared to the general study population.
Timeline
Enrollment of study participants began on September 1, 2023.
Enrollment of study participants concluded on March 31, 2024.
The follow-up period for study participants concluded on March 31, 2025.
Health Landscape
This research contributes to the growing body of knowledge regarding the longevity of adult vaccinations for respiratory pathogens. It sits within a broader medical effort to determine whether RSV prevention will require periodic revaccination similar to annual influenza protocols.
If you are immunocompromised or aged 80 or older, it is worth discussing the duration of your past RSV protection with your physician. Given the $350 estimated cost per dose, talk to your doctor about whether recent data supports a conversation regarding your specific vaccination schedule.
The takeaway
Protection from the RSV vaccine appears to decrease over time, with the most significant shifts occurring in high-risk groups. Patients should continue to monitor their overall respiratory health and consult with a doctor to determine if their individual risk profile warrants a follow-up conversation.
Further reading
For broader context on managing respiratory health, visit our Asthma section.
Source note: This article includes information reported by Medscape.
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