BACKGROUND AND PURPOSE:

• Maternal vaccination with the tetanus, diphtheria, and acellular pertussis vaccine (Tdap) is recommended in many countries to protect against infant pertussis
• Laverty et al. (Pediatrics, 2021) evaluated the long-term safety of exposure to Tdap vaccination during pregnancy

METHODS:

• Population-based retrospective cohort study
  • Ontario, Canada
  • Multiple province-wide health administrative databases
• Population
  • All live births between April 2012 and March 2017
• Exposure
  • Prenatal Tdap
• Study design
  • Children were followed for up to 6 years (birth to end of follow-up)
  • Tdap vaccination during pregnancy was determined using vaccine-specific fee codes
  • Children in the exposure group were propensity score matched to unexposed children in a 1:5 ratio
• Primary outcomes
  • Immune-related outcomes: Infectious diseases | Asthma
  • Nonimmunue-related outcomes: Neoplasm | Sensory disorders
  • Nonspecific morbidity: Urgent or inpatient health service use

RESULTS:

• 625,643 live births during study period
  • Tdap exposure: 1.9% (12,045 births)
• There were no significantly increased risks of adverse childhood outcomes with prenatal Tdap exposure
• Tdap exposure was associated with a decreased risk of
  • Upper respiratory infections
    • Adjusted incidence rate ratio (RR) 0.94 (95% CI, 0.90 to 0.99)
  • Gastrointestinal infections
    • Adjusted incidence RR 0.85 (95% CI, 0.79 to 0.91)
  • Urgent and inpatient health service use
    • Adjusted incidence RR 0.93 (95% CI, 0.91 to 0.96)

CONCLUSION:

• There was no association between prenatal Tdap exposure and adverse childhood health outcomes followed up to 6 years
• The authors state

Exposure to Tdap during pregnancy was not associated with any increased risk of infection, asthma, neoplasm, sensory disorders, or urgent and inpatient health service use in children in their first 6 years of life, supporting the long-term safety of Tdap administration in pregnancy

Learn More – Primary Sources:

Health Outcomes in Young Children Following Pertussis Vaccination During Pregnancy

Related ObG Topics:

Vaccination in Pregnancy: CDC Recommendations and ACOG Update

Results from the FluMum Study: Flu and Pertussis Vaccine Safety  

Are Tdap and Polio Vaccines Safe During Pregnancy?

Do Prenatal Tdap Vaccines Increase Risk for Autism?

More Evidence that Maternal Influenza Vaccination is Safe and Effective