RSV vaccine shows ‘quite impressive’ ability to prevent hospitalization in older adults

Key takeaways:

• Vaccines effective against RSV-associated ED visits, hospitalizations and ICU admissions.
• Reductions in hospitalizations could help produce major savings in health care, a researcher said.

Respiratory syncytial virus vaccines proved highly effective at preventing hospitalization and ED visits in older adults, even in those with immunocompromising conditions, results from an observational analysis showed.

The findings, published in The Lancet, are consistent with previously reported data on respiratory syncytial virus (RSV) vaccine effectiveness.

“Unlike this data study, clinical trials for the RSV vaccine were underpowered to access the effectiveness of the vaccines against severe disease requiring hospitalization,” Shaun Grannis, MD, MS, a professor of family medicine at the Indiana University School of Medicine, said in a press release. “Addressing this gap in evidence, we were able to use the power of big data to determine RSV vaccine effectiveness, information needed to inform vaccine policy.”

In June 2023, the CDC’s Advisory Committee on Immunization Practices said that adults aged 60 years or older may receive one of the two RSV vaccines approved by the FDA after talking with their doctors about getting vaccinated.

The 2023-2024 respiratory disease season marked the first where the two FDA-approved vaccines — GSK’s Arexvy and Pfizer’s Abrysvo — became available and recommended.

Grannis and colleagues used a test-negative study designed to compare the effectiveness of the RSV vaccine in adults aged 60 years or older admitted to a hospital or who had an ED visit for an RSV-like illness between Oct. 1, 2023, and March 31, 2024. The analysis employed data from an electronic health record-based records collaboration between the CDC and nine health care systems in eight U.S. states that track patient characteristics and outcomes of respiratory virus-related vaccines.

Overall, 36,706 (5%) hospitalizations and 37,842 ED visits (7%) included in the analysis corresponded with a positive RSV test.

Researchers reported a vaccine effectiveness rate of 80% (95% CI, 71%-85%) against RSV-associated hospitalizations and 81% (95% CI, 52%-92%) against RSV-associated ICU admission, death or both among adults without immunocompromising conditions.

“No vaccine is 100% effective. An 80% vaccine effectiveness rate is quite impressive and higher than we see, for example, with the influenza vaccine,” Brian E. Dixon, PhD, MPA, FACMI, FHIMSS, FAMIA, MACE, the director of public health informatics at the Regenstrief Institute and study co-author, said in the release.

Meanwhile, further results showed a vaccine effectiveness rate of 73% (95% CI, 48%-85%) against RSV-associated hospitalization among adults with immunocompromising conditions.

Grannis and colleagues determined vaccine effectiveness to be 77% (95% CI, 70%-83%) against RSV-associated ED visits across among adults without an immunocompromising condition.

They noted similar vaccine effectiveness against hospitalizations and ED visits between those aged 60 to 74 years and those aged 75 years or older, and by vaccine type.

The researchers acknowledged several study limitations. For example, patients with RSV-positive encounters may have had an encounter for other reasons than RSV, which could have lowered vaccine effectiveness estimates.

Additionally, the EHR data used may not have captured all the patients’ underlying conditions.

“Studies like this one are critical to understanding the effects of prevention techniques like vaccination,” Dixon said. “The annual cost of RSV hospitalization for adults in the U.S. is estimated to be between $1.2 and $5 billion. Preventing up to 80% of hospitalizations could result in major savings for consumers and the health system.”

References:

• Big data, real world, multi-state study finds RSV vaccine highly effective in protecting older adults against severe disease, hospitalization and death. Available at: https://www.regenstrief.org/article/multi-state-study-finds-rsv-vaccine-highly-effective/. Published Oct. 17, 2024. Accessed Nov.4, 2024.
• Payne A, et al. Lancet. 2024;doi:10.1016/S0140-6736(24)01738-0.