1393 - Factors Associated with Co-administration of Pentavalent DTaP-IPV/Hib and Monovalent Hepatitis B Vaccine in the United States (US)

Background: The US vaccination schedule includes DTaP, IPV, Hib and HepB doses in the first 6 months of life. A previous analysis found variability in the timing of HepB doses in infants receiving DTaP-IPV/Hib. We explored factors associated with co-administration of DTaP-IPV/Hib and HepB on the same day.

Methods: This was a retrospective study using the MarketScan® commercial claims and encounters database. Infants born from 1 July 2010 - 30 June 2016, continuously enrolled in an insurance plan for ≥ 13 months and receiving ≥ 3 DTaP-IPV/Hib doses were included.
Infants were assessed for HepB claims relative to the first and third DTaP-IPV/Hib doses. Because a HepB birth dose was assumed, the first HepB claim from 29 - 169 days following birth was counted as Dose 2, and the second claim from 170 days - 12 months as Dose 3. Associations between demographic, provider, and insurance characteristics, receipt of other pediatric vaccines, and co-administration of DTaP-IPV/Hib and HepB were analyzed using multivariate logistic regression.

Results: Among 165,553 infants who received a first DTaP-IPV/Hib dose, 60.7% received HepB Dose 2 on the same day. Among 162,217 infants who received a third DTaP-IPV/Hib dose, 45.1% received HepB Dose 3 on the same day.
Infants in the Northeast were less likely (OR=0.38, 95%CI=0.36-0.39), while those in the West were more likely (OR=1.41, 95%CI=1.36-1.46) than infants in the South to receive the first dose of DTaP-IPV/Hib and HepB Dose 2 on the same day. Infants vaccinated by pediatricians (OR=0.54, 95%CI=0.53-0.55) were less likely to receive the first dose of DTaP-IPV/Hib and HepB Dose 2 on the same day compared to infants vaccinated by family physicians. Infants who received PCV on the same day as the first dose of DTaP-IPV/Hib were more likely to receive HepB Dose 2 (OR=6.96, 95%CI=6.30-7.70) that day. These factors were also associated with co-administration of the third dose of DTaP-IPV/Hib and HepB Dose 3.

Conclusion: Differences in co-administration of DTaP-IPV/Hib and HepB were associated with region of residence, provider type and co-administration of PCV. The reasons underlying these differences merit exploration. A hexavalent vaccine containing DTaP, IPV, Hib, and HepB could improve timeliness of HepB vaccination, while reducing the number of injections during infancy.