Methods: Study subjects included children aged 19-35 months with adequate provider verified vaccination data from the 2013 National Immunization Survey Child (n=13,460). MOV were quantified by determining the number of medical visits a child made when another vaccine was administered during eligibility for HAV vaccine, but HAV was not administered. Bivariate and multivariate polytomous logistic regression was used to assess the association of MOV with child and maternal demographic, socio-economic and geographic covariates.
Results: In 2013, 85% of children in our study population had initiated the HAV vaccine series, and 60% received two or more doses. Children with 2+ MOV initiated the vaccine series 6 months later than children with zero. Children who received zero doses of HAV vaccine had an average of 1.8 MOV compared to 0.4 MOV in those with two doses. Children who were younger, had younger mothers, had ever received WIC benefits, lived below the poverty line or lived in a state with childcare or school entry mandates were less likely to have MOV for HAV, while children with more educated mothers or married parents were more likely have MOV for HAV.
Conclusion: Addressing MOV for HAV may offer a way to improve coverage for HAV vaccination in children. More research is needed to understand why children are not having the vaccine administered when eligible.