The Advisory Committee on Immunization Practices (ACIP) recommends maternal immunization (MI) with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during every pregnancy, preferably between 27-36 weeks of gestation, as well as influenza vaccination for all women who are pregnant or who might be pregnant in the influenza season.
This retrospective cohort analysis characterizes the rate of Tdap and influenza vaccination among large national samples of pregnant women in the U.S. using administrative claims data. The MarketScan® Commercial Claims and Encounters (Commercial) and the Multi-State Medicaid Databases (Medicaid) were used to identify pregnancies between 01/01/2010 04/30/2017. Diagnosis and procedure codes that describe gestational age at pregnancy end were used to estimate the date of last menstrual period (LMP) or the index date (Fig. 1). Eligible pregnancies had ≥6 months of continuous enrollment prior to index date (baseline) through 60 days after pregnancy end (follow-up). Maternal Tdap and influenza immunization rates are described by calendar year of pregnancy end. Analyses are reported separately for Commercial and Medicaid cohorts.
A total of 1,862,705 and 628,079 eligible pregnancies in the Commercial and Medicaid databases, respectively, were identified. After the 2013 ACIP recommendation to administer Tdap vaccination during each pregnancy, the proportion of pregnancies vaccinated against Tdap was 39% in 2014 and increased to 54% in 2016 for the Commercial cohort (Fig. 2). A similar trend for Tdap MI was observed for the Medicaid cohort (Fig. 3). In 2016, 41% and 25% of all pregnancies received influenza vaccination in the Commercial and Medicaid cohorts, respectively. Tdap and influenza MI rates also varied by several factors, including maternal age group, geographic region, urban/rural location, and race/ethnicity.
In this analysis of large claims databases, for pregnancies ending in 2016 in the Commercial cohort, over 50% received Tdap vaccination and over 40% received influenza vaccination, whereas, in the Medicaid cohort, 30% of all pregnancies were vaccinated against Tdap and 25% received influenza vaccination.
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