Background: Concerns regarding vaccine safety are a barrier to influenza vaccine uptake among pregnant women
Methods: Using data from the HealthPartners VSD study population we conducted a cohort-matched design to compare risks for acute events following TIV vaccination between vaccinated and unvaccinated pregnant women. Women 14-49 years of age who were pregnant during the 2002-2003 through 2008-2009 influenza seasons and had continuous HP insurance coverage from 6 months prior pregnancy and 2 months after end of pregnancy (17 months) were eligible. Women who received TIV two weeks or more after estimated pregnancy start date and at least one week before pregnancy outcome date were matched 1:2 (by age and pregnancy start date) to unvaccinated pregnant controls. In-patient and outpatient visits (0-3 days and 1-42 days after vaccination) for acute outcomes (identified via ICD-9 codes) were compared
Results: Our study population included 8108 TIV exposed and 9605 unexposed pregnant women (mean age=31 +/-5years). Thirty percent were vaccinated in the 1st trimester. Vaccinated women were more likely than controls to have pre-existing lung disease (p<.001). Acute events 0-3 days post-vaccination (allergic reaction, cellulitis, fever and malaise, rash, limb soreness, seizures, and altered mental status) were all rare and were less common in the vaccinated women (OR=0.34 (95% CI=0.14-0.81)) Acute safety events 1-42 days post-vaccination (neurologic disorders, thrombocytopenia, myocarditis, psychoses) were also rare and did not differ significantly between vaccinated and unvaccinated pregnant women (OR=0.85 (95% CI=0.61-1.17)
Discussion: TIV vaccination during pregnancy was not associated with increased risk for acute local or systemic reactions within 42 days of vaccination.