A recent multi-state study published in The Lancet confirms the high effectiveness of respiratory syncytial virus (RSV) vaccines in protecting older adults against severe disease. The real-world data analysis indicates that RSV vaccines provide approximately 80% protection against severe illness and hospitalization for individuals aged 60 and older during the 2023-24 respiratory disease season.
The study, a collaboration between the Centers for Disease Control and Prevention (CDC) and geographically diverse U.S. health care systems, encompassed data from Permanente Northwest, the University of Colorado, Intermountain Healthcare, the Regenstrief Institute, HealthPartners, and Kaiser Permanente Northern California, representing 230 hospitals and 245 emergency departments nationwide.
Key Findings on Vaccine Effectiveness
The research demonstrated that individuals over 60 who received the RSV vaccine reduced their odds of RSV-linked severe illness, hospitalization, admission to the ICU, and death by four-fifths compared to unvaccinated individuals. The benefits were particularly pronounced among those aged 75 and older, who are at the highest risk of severe disease.
According to Dr. Shaun Grannis, vice president for data and analytics at the Regenstrief Institute and a professor at the Indiana University School of Medicine, "We were able to use the power of big data to determine RSV vaccine effectiveness, information needed to inform vaccine policy."
Economic Impact of RSV Vaccination
Beyond the health benefits, the study also highlighted the potential economic impact of RSV vaccination. Dr. Brian Dixon, interim director and a research scientist with the Clem McDonald Center for Biomedical Informatics at Regenstrief Institute, noted that 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 these hospitalizations could result in major savings for consumers and the health system.
Comparison to Other Vaccines
While no vaccine is 100% effective, Dr. Dixon emphasized that "an 80% vaccine effectiveness rate is quite impressive and higher than we see, for example, with the influenza vaccine."
Abrysvo's Impact on Hospitalizations and ED Visits
Another retrospective analysis presented at IDWeek 2024, focusing on Abrysvo, found a 90% adjusted vaccine effectiveness against hospitalizations or emergency department (ED) visits among adults ages 60 and older during the first 5 months of vaccine availability (November 2023-April 2024). The study also indicated a 93% effectiveness against RSV-related acute respiratory illness (ARI) ED visits and 91% against RSV-related ARI ED visits or hospitalizations.
Addressing Limitations of Clinical Trials
Sara Tartof, PhD, MPH, of Kaiser Permanente, pointed out that clinical trials for RSV vaccines had a limited number of hospitalization and ED outcome visits, hampering vaccine efficacy estimation against more severe clinical outcomes. The real-world data helps to fill this gap, providing valuable insights into the vaccine's effectiveness in broader populations, including those with comorbidities and immunocompromised conditions.
