Infant Hospitalizations and Mortality After Maternal Vaccination

Area of Science:

• Obstetrics and Gynecology
• Pediatrics
• Vaccinology

Background:

• Current immunization guidelines recommend pregnant women receive influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines.
• Limited data exist on the long-term safety of vaccines administered during pregnancy for infants.
• This study investigates the association between maternal vaccination and infant health outcomes.

Purpose of the Study:

• To evaluate if maternal receipt of influenza and Tdap vaccines during pregnancy increases the risk of infant hospitalization or death within the first six months of life.

Main Methods:

• A case-control study was conducted using data from the Vaccine Safety Datalink (2004-2014).
• Singleton live birth pregnancies were included, with infant hospitalizations and mortality as primary outcomes.
• Maternal exposure to influenza and/or Tdap vaccines was analyzed using conditional logistic regression.

Main Results:

• The study included over 413,000 live births, with over 25,000 infant hospitalizations and 157 infant deaths.
• No significant association was found between maternal influenza vaccination and infant hospitalization (aOR: 1.00, 95% CI: 0.96-1.04).
• No significant association was found between maternal Tdap vaccination and infant hospitalization (aOR: 0.94, 95% CI: 0.88-1.01).
• No significant association was found between maternal influenza or Tdap vaccination and infant mortality.

Conclusions:

• Maternal vaccination with influenza and Tdap vaccines during pregnancy is not associated with an increased risk of infant hospitalization or death.
• These findings provide evidence supporting the safety of current recommendations for vaccinating pregnant women.
• The study reinforces the safety profile of key maternal immunizations.