The Food and Drug Administration (FDA) has approved Boostrix (tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine, adsorbed [Tdap]) for immunization during the third trimester of pregnancy to prevent pertussis in infants younger than 2 months of age.

Boostrix is a noninfectious vaccine for intramuscular administration that contains tetanus toxoid, diphtheria toxoid, and pertussis antigens. The vaccine was previously approved for active booster immunization against tetanus, diphtheria, and pertussis in individuals 10 years of age and older. Its effectiveness in preventing pertussis among infants younger than 2 months of age when administered during the third trimester of pregnancy was based on a reanalysis of data from an observational case-control study.

Boostrix was estimated to be 78% (95% CI, -38.0, 96.5) effective in preventing pertussis in infants younger than 2 months when administered during the third trimester of pregnancy based on data from 108 cases of pertussis in infants younger than 2 months of age (including 4 cases whose mothers received Boostrix during the third trimester) and 183 controls (including 18 whose mothers received Boostrix during the third trimester). This preliminary effectiveness estimate was found to be consistent when data from 4 observational studies that provided estimates of the vaccine effectiveness of the non-US formulation of Boostrix against pertussis in infants whose mothers were immunized during pregnancy were analyzed.

The safety of Boostrix administered during the third trimester was established in a randomized, controlled clinical study (ClinicalTrials.gov Identifier: NCT02377349) in which 341 pregnant individuals received the non-US formulation of Boostrix and 346 received placebo.  Results showed that the rates of reported adverse reactions following receipt of the non-US formulation of Boostrix administered during pregnancy were consistent with the rates following administration in the postpartum period. No vaccine-related adverse effects on pregnancy or on the fetus/newborn child were reported in the study.

“While vaccination is the best method for providing protection, infants younger than 2 months of age are too young to be protected by the childhood pertussis vaccine series,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research. “This is the first vaccine approved specifically for use during pregnancy to prevent a disease in young infants whose mothers are vaccinated during pregnancy.”

Boostrix is supplied in single-dose vials and single-dose prefilled syringes containing a 0.5mL suspension for injection. To provide protection against pertussis in infants younger than 2 months of age, it should be administered to pregnant individuals during the third trimester of pregnancy.

References

  1. FDA approves vaccine for use during third trimester of pregnancy to prevent whooping cough in infants younger than two months of age. News release. October 7, 2022. Accessed October 11, 2022. https://www.fda.gov/news-events/press-announcements/fda-approves-vaccine-use-during-third-trimester-pregnancy-prevent-whooping-cough-infants-younger-two
  2. Boostrix. Package insert. GlaxoSmithKline. 2022; Accessed October 11, 2022. https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Boostrix/pdf/BOOSTRIX.PDF