First Trimester Influenza Vaccination and Risks for Major Structural Birth Defects in Offspring

Journal of Pediatrics
August 2017 Volume 187, p1-340

Original Articles
First Trimester Influenza Vaccination and Risks for Major Structural Birth Defects in Offspring
Elyse Olshen Kharbanda, Gabriela Vazquez-Benitez, Paul A. Romitti, Allison L. Naleway, T. Craig Cheetham, Heather S. Lipkind, Nicola P. Klein, Grace Lee, Michael L. Jackson, Simon J. Hambidge, Natalie McCarthy, Frank DeStefano, James D. Nordin for the Vaccine Safety Datalink
Published online: May 24, 2017
To examine risks for major structural birth defects in infants after first trimester inactivated influenza vaccine (IIV) exposures.
Study design
In this observational study, we used electronic health data from 7 Vaccine Safety Datalink sites to examine risks for selected major structural defects in infants after maternal IIV exposure. Vaccine exposures for women with continuous insurance enrollment through pregnancy who delivered singleton live births between 2004 and 2013 were identified from standardized files. Infants with continuous insurance enrollment were followed to 1 year of age. We excluded mother–infant pairs with other exposures that potentially increased their background risk for birth defects. Selected cardiac, orofacial or respiratory, neurologic, ophthalmologic or otologic, gastrointestinal, genitourinary and muscular or limb defects were identified from diagnostic codes in infant medical records using validated algorithms. Propensity score adjusted generalized estimating equations were used to estimate prevalence ratios (PRs).
We identified 52 856 infants with maternal first trimester IIV exposure and 373 088 infants whose mothers were unexposed to IIV during first trimester. Prevalence (per 100 live births) for selected major structural birth defects was 1.6 among first trimester IIV exposed versus 1.5 among unexposed mothers. The adjusted PR was 1.02 (95% CI 0.94-1.10). Organ system-specific PRs were similar to the overall PR.
First trimester maternal IIV exposure was not associated with an increased risk for selected major structural birth defects in this large cohort of singleton live births.