Some doctors worry about risk of preterm birth from FDA-approved RSV vaccine

PHOENIX (3TV/CBS 5) — This week, the FDA approved the first vaccine for pregnant women to prevent RSV in their babies. RSV is a common respiratory infection that can sometimes turn serious or even deadly for infants and older adults and it causes tens of thousands of hospitalizations every year.

The FDA approved the vaccine earlier this year for people 60 years and older and now the same shot is approved for women during pregnancy. Everyone agrees it’s a good thing that there is a new measure to protect babies from this dangerous virus, but some doctors said the benefits may not outweigh the risks in certain cases.

A study shows this Pfizer vaccine reduced the risk of RSV in babies by nearly 82% 90 days after birth when given to a pregnant woman. “The idea behind it is that it will be given to the pregnant person and then they will form the antibodies that then are passed on to the baby and they will protect the baby in the first six months of life, which is the highest risk age for complications from RSV,” said Dr. Wassim Ballan, division chief of infectious diseases at Phoenix Children’s Hospital.

But that doesn’t tell the full story if you ask OBGYN Dr. Greg Marchand. “I think the FDA did let us down a little bit here. I would have liked to see stronger language in the package insert and a narrower indication,” said Dr. Marchand.

The single-dose shot is approved for use at 32 through 36 weeks of pregnancy, but Dr. Marchand said the vaccine may not be the best option for everyone. “So, any strategy you’ve got to protect those newborns from RSV is going to be a good thing, but based on the data I’ve seen from this particular vaccine and its predecessor that was produced by a different company, I do have some concerns especially about this vaccine causing pre-term labor,” said Dr. Marchand.

Dr. Marchand points to a different company, GSK, ending a similar RSV vaccine trial in pregnant women earlier this year due to an increase in pre-term births in those given the vaccine. Dr. Ballan said the Pfizer data isn’t enough to cause concern. “Even though it did show that there’s maybe a little bit more premature births in the group that got the vaccine, it was actually not that statistically significant when compared to the other group,” said Dr. Ballan.

Dr. Ballan said all pregnant women should get this vaccine to protect their children, but Dr. Marchand said this isn’t the time for what he calls cookie-cutter medicine. “Now, I’m not saying that in all cases the danger of pre-term birth is going to outweigh the danger of RSV. Of course an RSV infection in a baby is a very dangerous thing, but I’d be very worried using this across the board,” said Dr. Marchand.

The vaccine is awaiting CDC approval and the FDA is requiring further studies to assess the risk of pre-term birth. The FDA said data in Pfizer’s trial is insufficient to prove their vaccine is causing pre-term births.

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