Neonates face a significant risk from Respiratory Syncytial Virus (RSV), often leading to severe bronchiolitis and pneumonia requiring hospitalization. Recent advancements include a maternal RSV vaccine (Abrysvo, Pfizer) and a monoclonal antibody (nirsevimab-alip, Beyfortus, Sanofi/Astra Zeneca), both FDA-approved to prevent lower respiratory tract disease in neonates.
Comparative Effectiveness
According to Helen Chu, MD, MPH, Professor of Medicine, Epidemiology, and Global Health at the University of Washington, both the maternal vaccine and the monoclonal antibody are designed to protect infants against severe RSV disease requiring hospitalization. Clinical trials for the maternal vaccine showed an efficacy of around 60% to 70% against RSV hospitalization. Similarly, the monoclonal antibody, administered at birth, demonstrated a comparable efficacy of 60% to 70% in clinical trials. Real-world data from Europe indicates that nirsevimab has reduced infant hospitalizations by 70%.
Administration and Duration
The maternal vaccine is administered between 32 and 36 weeks of gestation, transferring protective antibodies across the placenta to the baby, which last for the first 4 to 6 months after birth. Nirsevimab, on the other hand, is directly administered to the baby at birth and also provides protection for 4 to 6 months.
Logistical Challenges and Uptake
Despite the demonstrated protection, challenges exist in the implementation of both interventions. The maternal vaccine requires administration within a narrow gestational window (32-36 weeks), posing logistical hurdles. Furthermore, initial uptake of nirsevimab was below 20%. Reimbursement issues and the high cost of nirsevimab also present barriers to widespread use, particularly as early administration is crucial to protect infants who are most vulnerable at a very young age.
