Vaccinazione materna RSV, Nirsevimab dell'infante, o entrambi: analisi intermedia di un trial randomizzato.

BACKGROUND: Although both maternal respiratory syncytial virus (RSV) prefusion F vaccination (RSVpreF) and infant nirsevimab immunization have been approved for the prevention of RSV lower respiratory tract infections, the 2 have not been evaluated in a single study, and their sequential administration has not been studied systematically. METHODS: We performed a prospective, randomized, open-label, phase 4 study at 8 US sites of mother-infant pairs randomized 1:1:1:1 during pregnancy: maternal RSVpreF vaccine alone, maternal RSVpreF vaccine/infant nirsevimab at birth, maternal RSVpreF vaccine/infant nirsevimab at 3 months, or infant nirsevimab alone at birth. We are following the mother-inf