Pfizer's RSV Vaccine Abrysvo Clears Concerns Over Preterm Birth Risk, Safety For Pregnant Women, New Study Shows

According to a small study by Weill Cornell Medicine and New York-Presbyterian investigators, vaccinating mothers using Pfizer Inc’s PFE vaccine against respiratory syncytial virus (RSV) during late pregnancy to protect their newborns is not associated with an increased risk of preterm birth or other poor outcomes.

The FDA approved the Abrysvo (RSVpreF) vaccine last year. It targets women in their second or third trimesters to prevent RSV infections in newborns during their first six months.

Also Read: UK Chooses Pfizer Over GSK for Multi-Million Dose RSV Vaccine Contract.

In September 2023, the U.S. Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices recommended the RSVpreF vaccine be administered to most pregnant individuals from September to January in the U.S.

This is in contrast to GSK Plc’s GSK RSV adjuvanted vaccine, which is not approved for use in pregnant individuals based on a trial that was terminated early due to an elevated risk of premature birth and associated neonatal deaths.

Although the FDA approved the RSVpreF vaccine, the gestational age window was limited to 32 0/7 to 36 6/7 weeks due to concerns about the numerical difference in preterm birth among participants who received the RSVpreF vaccine from 24 to 36 weeks gestation.

The findings indicated no significant statistical difference in preterm birth rates, with vaccinated women showing a rate of 5.9%, compared to 6.7% in unvaccinated women.

The study analyzed electronic health records from two New York City hospitals, focusing on births from September 2023 to late January 2024.

Data published in the Jama Network comes from 2,973 pregnant individuals. The researchers add that though the data support the safety of prenatal RSVpreF vaccination, further investigation into the risk of hypertensive disorders of pregnancy (HDP) is warranted.

Price Action: PFE shares are down 0.60% at $27.88 at the last check on Monday.

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