Maternal RSV Vaccination and Complementary Infant-Protection Strategies in Singapore: A Modified Nominal Group...

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease in infants and a major contributor to infant morbidity and mortality. A previous Singapore consensus addressed RSV disease burden and the role of the monoclonal antibody, nirsevimab, but did not extend to maternal RSV vaccination or its complementary use with long-acting monoclonal antibodies (mAbs). We sought structured expert consensus on positioning maternal RSV vaccination and a complementary prevention strategy in Singapore.

A modified nominal group technique (mNGT) was used. A multidisciplinary panel of seven Singapore-based experts in obstetrics, including maternal-fetal medicine and paediatrics (respiratory, infectious disease, immunisation, and immunology), reviewed a pre-circulated targeted evidence review and four draft statements across four themes (burden, preventive pathways, maternal RSV vaccination, and complementary strategy), with the opportunity to submit written comments in advance. At a live virtual meeting on 16 June 2026, facilitated by a medical communications agency, the panel first discussed the evidence underpinning each draft statement and then voted openly (non-anonymously) on each statement in sequence. Consensus was predefined as ≥70% agreement. Statements that did not reach consensus were refined collectively, with each expert contributing in turn, and re-voted.

All seven experts attended and voted. Two statements reached consensus in Round 1 (Theme 2, 7/7; Theme 4, 6/7) and two after a single round of modification (Theme 1, 0/7 and then 7/7 after "first months of life" was specified as "first six months of life"; Theme 3, 3/7 and then 6/7 after "eligible pregnancies" was explicitly defined). The final statements cover RSV burden in the first six months of life, informed choice of preventive pathway, maternal RSV vaccination as an antenatal option for eligible pregnancies, and a complementary strategy in which a long-acting mAb (nirsevimab) is considered for infants not adequately protected by maternal vaccination.

This expert consensus supports maternal RSV vaccination as an antenatal prevention option for eligible pregnancies in Singapore and a complementary strategy with nirsevimab for infants not adequately covered by maternal vaccination. The statements represent expert consensus intended to inform, not replace, national guidance.