May 11, 2022. “Results from a prespecified pooled analysis of the pivotal Phase 3 MELODY and Phase 2b nirsevimab trials demonstrated an efficacy (relative risk reduction versus placebo) of 79.5% (95% CI 65.9 to 87.7; P<0.0001) against medically attended LRTI, such as bronchiolitis or pneumonia, caused by RSV in infants born at term or preterm entering their first RSV season.
In a separate pooled post-hoc analysis of the trials, blood samples taken from infants dosed with nirsevimab exhibited RSV neutralizing antibodies that were approximately 50-fold higher than baseline at Day 151 post-dose.
RSV neutralizing antibody levels remained greater than 19-fold higher than placebo recipients with no known RSV infection through Day 361, suggesting protection may extend beyond Day 151.
The safety profile across the nirsevimab and placebo groups, as reported in previous trials, remains similar.
These findings contribute to the growing body of evidence suggesting that nirsevimab can protect all infants through their first RSV season with a single dose.”