Why is the Tdap Vaccine in Category C?

The Tdap vaccine is routinely recommended for all pregnant women, so why would it be in the FDA Category C?

The FDA has actually removed the pregnancy categories.

We should start by stating that “risk-benefit decisions regarding use of a drug during pregnancy are more complex than the category designations suggest.”

Why is the Tdap Vaccine in Category C?

Anyway, the category designations are no longer being used on new drugs and vaccines.

“In December of 2014, the FDA published the Content and Format of Labeling for Human Prescription Drug and Biological Products; Requirements for Pregnancy and Lactation Labeling, referred to as the “Pregnancy and Lactation Labeling Rule” (PLLR or final rule). The PLLR removes pregnancy letter categories – A, B, C, D and X. Instead, under the final rule, narrative summaries of the risks of a drug during pregnancy and discussions of the data supporting those summaries are required in labeling to provide more meaningful information for clinicians.”

Guidelines for Vaccinating Pregnant Women

So is it still Category C?

Yes, for now. Few vaccines have converted to the new labeling system yet, which still leaves us with:

  • Pregnancy Category B: Tdap (Boostrix) – Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus during the first trimester (and there is no evidence of risk in later trimesters).
  • Pregnancy Category C: Tdap (Adacel) – Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks OR Animal reproduction studies have not been conducted and there are no adequate and well-controlled studies in humans.

Of course, the Vaccine Safety Datalink has published more than 14 studies “related to pregnancy and vaccination during pregnancy” and has used “data to study the health of children born to women who were vaccinated during pregnancy.”

And many of these studies are about the Tdap vaccine!

“There are no theoretical or proven concerns about the safety of the Tdap vaccine (or other inactivated vaccines like Tdap) during pregnancy. The shot is safe when given to pregnant women.”

Frequently Asked Questions for Pregnant Women Concerning Tdap Vaccination

This will likely be reflected when we get new labels for these vaccines, with wording that makes it clear that Tdap vaccines are safe in pregnancy.

what to know about the tdap vaccines and their category c designation

Tdap vaccines still have a Category C designation simply because their labels haven’t been updated to reflect the latest safety studies.

More on Tdap Vaccines and Category C

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