FDA just approved Pfizer vax ABRYSVO in pregnancy to protect infants against RSV despite a 20%! higher rate of preterm birth in vax group (5.7%) vs controls (4.7%)

Pfizer Inc. (NYSE: PFE) announced today that the U.S. Food and Drug Administration (FDA) has approved ABRYSVO™ (Respiratory Syncytial Virus Vaccine), the company’s bivalent RSV prefusion F (RSVpreF) vaccine, for the prevention of LRTD and severe LRTD caused by RSV in infants from birth up to six months of age by active immunization of pregnant individuals at 32 through 36 weeks gestational age.

https://www.pfizer.com/news/press-release/press-release-detail/us-fda-approves-abrysvotm-pfizers-vaccine-prevention-0

Here's the MATISSE study, the basis of the VRBPAC approval

Table above from this (non open access) study

Pfizer in the VRBPAC meeting said all they would've needed to determine if preterm birth signal real was enroll 5,000 instead of 3,600 in each arm🤦‍♀️https://t.co/PZO3XDLdMw

— Tracy Høeg, MD, PhD (@TracyBethHoeg) August 21, 2023

My guess is we'll need to rely on other countries to do RCTs to get the answer re preterm birth

But given the fact this signal was seen in all 4 formulations of the vax (R) + the GSK RSV vax (was abandoned due to preterm birth risk) it seems highly UNlikely the signal's not real pic.twitter.com/aE0DEJeC7y

— Tracy Høeg, MD, PhD (@TracyBethHoeg) August 21, 2023