FDA Approves Vaccine to Prevent Whooping Cough in Newborns by Vaccinating Mothers at Third Trimester

The vaccine prevents whooping cough in infants younger than 2 months. It can be safely administered to mothers who are in their third trimester.

The FDA approved the tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine, adsorbed (Tdap) (Boostrix; GlaxoSmithKline) for vaccination of mothers in the third trimester of pregnancy. Although approved for infants younger than 2 months of age, vaccination of mothers at the third trimester stage can protect the infant at birth against pertussis. The approval noted that Tdap can be given to patients at a 0.5-mL dose, making it the third in a series of FDA approvals for pertussis over the last 20 years.

Since children aged 2 months of age or younger are not eligible to receive an actual vaccine themselves, administering the Tdap vaccine to the mother can boost the infant’s immune system by boosting antibodies in the mother, who then transfers the antibodies to the developing fetus.

“Babies are at highest risk for getting pertussis and having serious complications from it,” said Peter Marks, MD, PhD, director of the Center for Biologics Evaluation and Research at the FDA, in a press release.

Pertussis, better known as whooping cough, is a highly contagious, but common, respiratory disease that can affect all age groups in the United States, Marks said in the press release. Whooping cough comes from the “whooping” sound of someone trying to catch their breath after suffering from a coughing fit.

According to the CDC, although only 4.2% of US cases occur in this age group, 31% of infants who contract the disease who are also younger than 6 months go to the hospital due to the illness.

To assess the efficacy and safety of Tdap in this population, researchers conducted a randomized, placebo-controlled study, enrolling pregnant women who had not yet given birth. In the study, researchers identified 680 pregnant women who were in their third trimester. Among participants, 340 were given a non-US Tdap formulation, and 340 received a saline placebo. Following childbirth, placebo patients were given the international Tdap vaccine.

The non-US formulation is largely considered to be similar to the US formulation; for this reason, since the safety of the non-US formulation has been assessed and approved in prior clinical trials, the safety of the US-formulation also provided further data supporting the FDA approval.

Following the study, no woman reported any vaccine-related adverse effects on their newborn, fetus, or on the pregnancy itself. However, pain, redness around the injection site, fatigue, and gastrointestinal symptoms were reported among individuals who participated in prior clinical studies.

The FDA first approved Tdap as a single booster against tetanus, diphtheria, and pertussis for children aged 10 to 18 in 2005. The FDA later approved Tdap for individuals aged 19 and older. In this second approval, the FDA allowed individuals to receive a second dose of Tdap if 9 years had passed since their first vaccination.

“This is the first vaccine approved specifically for use during pregnancy to prevent a disease in young infants whose mothers are vaccinated,” Marks said in the press release.

Reference

U.S. Food & Drug Administration. FDA Approves Vaccine for Use During Third Trimester of Pregnancy to Prevent Whooping Cough in Infants Younger Than Two Months of Age. October 7, 2022. FDA website. Accessed on October 7, 2022. https://www.fda.gov/news-events/press-announcements/fda-approves-vaccine-use-during-third-trimester-pregnancy-prevent-whooping-cough-infants-younger-two?utm_medium=email&utm_source=govdelivery