Overview
This interview discusses therapies to reduce severe Respiratory Syncytial Virus (RSV) illness, focusing on monoclonal antibodies and vaccines for infants, children, pregnant individuals, and adults over 60, as well as current CDC recommendations, efficacy, and safety concerns.
RSV Infection: Epidemiology and Risk Factors
- RSV is a leading cause of acute lower respiratory infections, particularly severe in children under 2 and adults over 60.
- Annually, RSV leads to 58,000–80,000 pediatric hospitalizations (100–300 deaths) and 60,000–160,000 hospitalizations (6,000–10,000 deaths) in adults 65+ in the US.
- High-risk groups include premature infants, children with chronic diseases, older adults with comorbidities, and immunocompromised individuals.
Monoclonal Antibody Therapies in Children
- Palivizumab has been FDA-approved since 1998, administered monthly for five months to high-risk infants and children.
- Candidates include infants born before 29 weeks, those with chronic lung or heart disease, anatomical airway issues, or immunocompromise.
- Palivizumab reduces severe RSV risk by 55% over 150 days post-dose.
- Nirsevimab, FDA-approved July 2023, is given once per RSV season to infants under 8 months whose birthing parent was not vaccinated.
- Nirsevimab is 79.5% effective in preventing severe RSV in the 150 days after dosing.
Updated Recommendations During Nirsevimab Shortage
- CDC prioritizes Nirsevimab for infants <8 months at season start unless the birthing parent had RSV vaccination.
- Palivizumab should be given if Nirsevimab is unavailable.
- Only certain children (chronic lung disease, severe immunocompromise, cystic fibrosis, American Indian/Alaska Native children) may receive a second dose in a new season.
Maternal Vaccination
- The Pfizer Abrisvo vaccine is FDA-approved for pregnant individuals after 32 weeks' gestation.
- Abrisvo is 82% effective in preventing severe RSV in the first 90 days of life and 70% within six months in infants.
RSV Vaccines in Adults 60+
- Both Abrisvo (Pfizer) and Arexvy (GSK) block RSV fusion protein and are protein-based vaccines.
- Abrisvo: 67% efficacy (two symptoms), 86% (three+ symptoms), 62% (any infection); trial primarily healthy individuals.
- Arexvy: 83% efficacy (lower respiratory infection), 94% (severe infection), 72% (any infection); immunocompromised excluded.
CDC Recommendations for Older Adults
- CDC advises shared patient-provider decision-making for RSV vaccination in adults 60+.
- Discussion should consider individual risk, benefits, and preferences.
Safety and Adverse Events
- Abrisvo: Two Guillain-Barre cases in >30,000 trial participants; overall risk remains low.
- Arexvy: Higher rate (~60%) of mild to moderate injection site reactions; some Guillain-Barre cases reported in smaller studies, under investigation.
Additional Considerations
- RSV vaccination may prevent complications like cardiac events and surpass influenza in complication frequency for older adults.
- Provider-patient discussions are essential in vaccine decision-making.
Recommendations / Advice
- Discuss RSV vaccination with eligible patients to evaluate individual risks and benefits, especially for high-risk groups.
- Monitor patients for rare but serious adverse events such as Guillain-Barre syndrome, particularly after vaccination.