343: Reactogenicity of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) in pregnant women

The CDC’s Advisory Committee on Immunization Practices recommends administration of Tdap vaccine during each pregnancy to provide passive immunity for young infants against pertussis. Although current studies support overall safety of Tdap during pregnancy, information regarding reactogenicity, particularly after repeated Tdap, was limited. Therefore, we compared rates of injection-site and systemic reactions following Tdap vaccination among pregnant versus nonpregnant women. Pregnant (gestational age 20-34 weeks) and nonpregnant women aged 18-45 years were prospectively enrolled from university affiliated clinics in NC and TN. Rates of injection-site and systemic reactions were assessed through 7 days post-vaccination. Participants recorded daily temperature, solicited local and systemic symptoms using a severity scale (e.g., pain, tenderness, malaise) and measured injection-site erythema/induration if indicated. Responses were compared between pregnant and nonpregnant subjects using Chi-square. We enrolled 361 pregnant (median age 29.0) and 161 non-pregnant (median age 28.6) women. Among pregnant women, 88.7% were non-Hispanic ethnicity with 68.4% Caucasian and 31.1% black race. Median gestational age at vaccination was 29.3 weeks and 53% had prior Tdap. Among pregnant women, severe local and systemic reactions or any fever were uncommon (≤2%) (Table). Among non-pregnant women, 95.2% were non-Hispanic ethnicity with 78.6% Caucasian and 14.4% black race; 69% had prior Tdap. Among nonpregnant women, severe reactions were also uncommon (≤2%) (Table). Rates of moderate to severe injection-site pain and malaise were higher among pregnant compared with nonpregnant women (p <0.05); however, events resolved without medical intervention. Rates of other reactions were similar between groups. Tdap vaccine is well tolerated in both pregnant and nonpregnant women. Moderate/severe injection-site pain and malaise occurred more frequently among pregnant women but was consistent with clinically reported rates for Tdap vaccine.