Test-Negative Study: RSV Vaccine May Reduce Hospitalizations and ED Visits in Adults Aged ≥60
16 Nov, 2024 | 14:18h | UTCBackground: Respiratory syncytial virus (RSV) is a significant cause of morbidity and mortality among older adults in the USA, with an estimated 100,000–160,000 RSV-associated hospitalizations annually in those aged 60 years and older. In 2023, RSV vaccines were recommended for this population, showing efficacy in clinical trials. However, real-world effectiveness data, particularly against severe outcomes like hospitalizations in high-risk groups, are limited.
Objective: To assess the real-world effectiveness of RSV vaccination against RSV-associated hospitalizations and emergency department (ED) encounters among adults aged 60 years and older during the 2023–24 RSV season in the USA.
Methods: A test-negative design analysis was conducted using data from the Virtual SARS-CoV-2, Influenza, and Other Respiratory Viruses Network (VISION), encompassing eight states. Adults aged ≥60 presenting with RSV-like illness and tested for RSV from Oct 1, 2023, to Mar 31, 2024, were included. Vaccination status was determined through electronic health records, immunization registries, and medical claims. Vaccine effectiveness (VE) was estimated by comparing the odds of vaccination among RSV-positive cases and RSV-negative controls, adjusting for age, sex, race and ethnicity, comorbidities, and geographic region.
Results: Among 28,271 hospitalizations for RSV-like illness in immunocompetent adults aged ≥60, VE against RSV-associated hospitalization was 80% (95% CI 71–85). VE against RSV-associated critical illness (ICU admission or death) was 81% (95% CI 52–92). In 8,435 hospitalizations among immunocompromised adults, VE was 73% (95% CI 48–85) against RSV-associated hospitalization. Among 36,521 ED encounters in immunocompetent adults, VE against RSV-associated ED visits was 77% (95% CI 70–83). VE estimates were consistent across age groups and vaccine products.
Conclusions: RSV vaccination effectively prevented RSV-associated hospitalizations and ED visits among adults aged ≥60 during the first season post-approval, including those at highest risk due to advanced age or immunocompromise.
Implications for Practice: These findings support recommending RSV vaccination for adults aged ≥60 to reduce severe RSV-related morbidity and mortality. Clinicians should consider advising eligible patients to receive the RSV vaccine to prevent hospitalizations and critical illness.
Study Strengths and Limitations: Strengths include a large, geographically diverse cohort and integrated medical, laboratory, and vaccination data, allowing robust VE estimates across subgroups. Limitations involve potential misclassification of vaccination status, residual confounding, and reliance on clinician-directed RSV testing, which may introduce bias.
Future Research: Further studies are needed to evaluate the duration of vaccine protection over multiple RSV seasons and to assess VE in other high-risk populations and settings.