RSV Vaccines for Older Adults: Second Season Recommendations 2026

What RSV Vaccines Are Available for Older Adults?

In May 2023, the FDA approved two RSV vaccines for adults aged 60 and older, marking the first time any RSV vaccines became available after decades of research setbacks. Arexvy, developed by GSK, is a recombinant protein vaccine containing the RSV prefusion F (preF) glycoprotein from RSV subtype A, combined with GSK's AS01E adjuvant system. The pivotal AReSVi-006 trial enrolled approximately 25,000 adults aged 60+ across 17 countries and demonstrated 82.6% efficacy against RSV-associated lower respiratory tract disease (LRTD) and 94.1% efficacy against severe RSV LRTD in the first season.

Abrysvo, developed by Pfizer, is a bivalent vaccine containing stabilized prefusion F proteins from both RSV subtype A and RSV subtype B, administered without adjuvant. The RENOIR trial (approximately 37,000 participants aged 60+) showed 66.7% efficacy against RSV-associated LRTD with at least two symptoms, and 85.7% efficacy against RSV-LRTD with three or more symptoms in the first season. Abrysvo is also FDA-approved for administration to pregnant individuals at 32-36 weeks gestation to provide passive immunity to newborns, making it dual-indicated.

Both vaccines are administered as single intramuscular injections. The ACIP recommended these vaccines under a shared clinical decision-making framework rather than a universal recommendation, meaning that the decision to vaccinate should be made through discussion between patient and clinician, considering individual risk factors, health status, and preferences. Adults at highest risk — including those with chronic heart or lung disease, diabetes, immunocompromising conditions, or residents of long-term care facilities — are most likely to benefit from vaccination.

What Does Second Season Data Show?

Two-season follow-up data from the pivotal trials of both vaccines have provided important insights into durability of protection. For Arexvy, GSK reported that efficacy against RSV-associated LRTD was 67.2% in the second season (compared to 82.6% in season one), based on the AReSVi-006 trial's ongoing follow-up. Against severe RSV-LRTD, second-season efficacy remained higher at 78.8%. These data suggest meaningful but declining protection over time, raising questions about the optimal timing for revaccination.

Pfizer's Abrysvo showed a similar pattern of waning. In the RENOIR trial's second-season analysis, efficacy against RSV-LRTD with two or more symptoms was approximately 56%, down from 66.7% in the first season. As of late 2025, neither manufacturer had yet received FDA approval for a booster dose, and clinical trials evaluating revaccination are ongoing. The ACIP has not yet established specific revaccination intervals but has signaled that guidance may be forthcoming as additional data mature.

Real-world effectiveness studies conducted through the CDC's VISION network and other surveillance platforms have generally corroborated the clinical trial findings. A CDC Morbidity and Mortality Weekly Report (MMWR) published in 2024 estimated vaccine effectiveness against RSV-associated hospitalization in adults 60+ at approximately 75% during the first season following vaccination. These real-world data are particularly important given that clinical trial populations may not fully represent the broader population of older adults with multiple comorbidities.

What About RSV Protection for Infants?

RSV is the leading cause of hospitalization in infants under 12 months in the United States, responsible for an estimated 58,000-80,000 hospitalizations and 100-300 deaths annually in children under 5. Nirsevimab (Beyfortus), developed by Sanofi and AstraZeneca, is a long-acting monoclonal antibody that binds to the prefusion form of the RSV F protein, providing passive immunization for approximately five months after a single intramuscular injection. The MELODY trial demonstrated 74.5% efficacy against medically attended RSV-associated lower respiratory tract infections in healthy term and late preterm infants.

The CDC and ACIP recommend nirsevimab for all infants younger than 8 months born during or entering their first RSV season (typically October through March in most of the continental US). Additionally, children aged 8-19 months who are at increased risk of severe RSV disease — including those with chronic lung disease of prematurity, hemodynamically significant congenital heart disease, severe immunocompromise, or severe cystic fibrosis — are recommended to receive nirsevimab entering their second RSV season. The initial 2023-2024 season saw significant supply shortages, but availability improved substantially for the 2024-2025 and 2025-2026 seasons.

An alternative approach for infant protection is maternal vaccination with Abrysvo (Pfizer), administered between 32 and 36 weeks of gestation during September through January. Maternal antibodies cross the placenta and provide passive immunity to the newborn during the first months of life. The MATISSE trial showed 81.8% efficacy against severe RSV-associated LRTD in infants within the first 90 days of life. The ACIP recommends either maternal Abrysvo vaccination OR infant nirsevimab, but not both, as there are no data on the added benefit of combining these approaches and cost-effectiveness analyses favor using one strategy per infant.