2698. Timing of Standalone Vaccine Administration in Infants Receiving DTaP-Based Combination Vaccines

Abstract

BackgroundThe recommended US infant immunization schedule includes doses of DTaP, IPV, Hib and HepB during the first 6 months of life. The majority of infants receive DTaP as one of the two pentavalent combination vaccines (DTaP-IPV/Hib or DTaP-HepB-IPV); standalone HepB or Hib are used to complement these combinations in compliance with the recommendations. Little is known about the timing of standalone vaccine administration in relation to DTaP-based combination vaccines.MethodsThis was a retrospective observational cohort study using the US MarketScan commercial claims and encounters database. Infants included in the study were continuously enrolled in the same insurance plan for ≥13 months after birth, born from 1 July 2010 through 30 June 2016, and had received ≥3 doses of a pentavalent vaccine. Outcomes included the proportion of infants receiving concomitant pentavalent and standalone vaccines, and the deviation in days when these vaccines were not administered on the same date. Birth doses of HepB were not registered in the database but were presumed to have been received; therefore, the first registered HepB claim was considered to be HepB Dose-2, and the second claim was presumed to be HepB Dose-3.ResultsAmong infants who received DTaP-IPV/Hib (n = 175,574), 94.8% had claims for ≥3 doses of HepB. Although coverage was high, only 60.7% received HepB Dose-2 on the same day as DTaP-IPV/Hib Dose-1 (around 2 months of age), and only 45.1% received HepB Dose-3 on the same day as DTaP-IPV/Hib Dose-3 (around 6 months of age) (Figure 1). Many infants (46.2%) received HepB Dose-3 after the third dose of DTaP-IPV/Hib. Among infants who received DTaP-HepB-IPV (n = 97,206), 89.9% had claims for the recommended number of Hib doses; most (91% to 98%) of these doses were administered on the same day as doses of DTaP-HepB-IPV (Figure 2).ConclusionThere was variability in the timing of HepB doses in infants receiving DTaP-IPV/Hib. A newly licensed hexavalent vaccine, DTaP-IPV-Hib-HepB, could synchronize and simplify the HepB administration schedule ensuring that more infants have completed the series by 6 months of age. Disclosures All authors: No reported disclosures.