MATISSE Trial: Maternal RSV Vaccine Outcomes

Dr. Chapa’s Clinical Pearls.

In most regions of the United States, RSV season starts in the fall and peaks in the winter. In September 2023, the ACOG released a Practice Advisory recommending a single dose of Pfizer’s RSV vaccine (Abrysvo) for eligible pregnant individuals between 32 0/7 and 36 6/7 weeks of gestation who do not have a planned delivery within 2 weeks, using seasonal administration, to prevent RSV lower respiratory tract infection (LRTI) in infants. This is recommended from September to January. Currently, the US recommendation is for this to be given once, with subsequent deliveries receiving neonatal Beyfortus in RSV season. The recommendation from NICE is to have this vaccination with every pregnancy. The prescribing information for Abrysvo includes a warning to inform patients that a numerical imbalance in preterm births in Abrysvo recipients (5.7%) occurred compared to those who received placebo (4.7%). This imbalance was only seen in trial participants residing in low- to middle-income countries with no temporal association to vaccination or association with other adverse events in the mother or the newborn. Now, that phase 3 clinical data has gone through peer review and is a new publication. This is the MATISSE global study and will be officially published in the Green Journal February 2025…but we will summarize the results NOW in this episode! Listen in for details.