Some experts have criticised Pfizer for not informing pregnant women in its trial of maternal respiratory syncytial virus vaccine that trials of a similar vaccine were halted over a potential risk of preterm birth. Others think that notification would have been premature and caused unnecessary anxiety. Hristio Boytchev reports
A debate has broken out over whether Pfizer should have told pregnant women participating in its trial of maternal respiratory syncytial virus (RSV) vaccination that a trial of a similar vaccine was halted over a safety signal around preterm birth, The BMJ can report. Both GSK and Pfizer were developing recombinant RSV F protein vaccines to inoculate pregnant women and protect their babies against RSV, a major cause of infant death globally.
GSK halted its phase 3 vaccine trial on 28 February 2022 after a safety signal emerged: a possible increased risk of preterm births and neonatal deaths. In the vaccine arm, 6.81% of births were preterm (95% confidence inter