OBJECTIVE: In October 2012 the Advisory Committee on Immunization Practices (ACIP) advised Tdap vaccination during every pregnancy, optimally at 27-36 weeks. Our objectives were 1) to examine 2010-2014 temporal trends in overall Tdap vaccination rates, and 2) to identify factors associated with failure to optimally vaccinate.
STUDY DESIGN: Using MarketScan Commercial Claims and Encounters Databases we identified 1,222,384 privately-insured US women with a pregnancy (live birth or stillbirth; singleton or multiples) at 20 weeks from 1/1/10 - 12/31/14. Women were censored at delivery or at end of health plan enrollment. We categorized Tdap vaccination as early-prenatal (<27 wks); optimalprenatal (27-36 wks); late-prenatal (37 wks); postpartum (1 week PP), and none. We measured temporal trends in overall Tdap vaccination rates and identified factors associated with failure of optimal-prenatal vaccination. We developed a Cox hazards model to estimate adjusted rate ratios (adj RRs) and 95% confidence intervals (CI) for factors associated with failure of optimal-prenatal vaccination.
RESULTS: During the study period, overall only 241, 543 (19.8%) of 1,222,384 pregnant women received Tdap. By 12/2014 44% of women received Tdap. After the 2012 ACIP guidelines Tdap vaccination rates increased sharply, and the majority occurred at the optimal-prenatal time (Figure 1). Overall Tdap vaccination rates varied by maternal age, presence of other dependent children, overnight hospitalization in pregnancy, and geographic region of residence (Figure 2). In adjusted analyses [adj RR(95%CI)], optimalprenatal Tdap vaccination rates were significantly lower among women aged < 25 vs 25 [.77 (.76-.79)]; those with other dependent children vs none [.81 (.76-.79)]; overnight hospitalization in pregnancy vs none [.81 (.75-.87)]; and women living in the Northeast [.70 (.69-.71)], South [.60 (.59-.61)], or West [.75 (.74- .76)] vs the Midwest.
CONCLUSION: Despite 2012 ACIP guidelines, in 2014 less than half of privately-insured U.S. pregnant women received Tdap. Research is warranted to understand barriers to Tdap vaccination during pregnancy. Efforts are needed to improve overall and optimalprenatal Tdap vaccination rates, particularly in younger women, those with other children, and those living outside of Midwest states.
