Population and sub-national (district) level diversity in missed and dropout of different doses of hepatitis-B vaccine among Indian children aged 12-59 months.

Initiating with a birth dose and a full immunization against hepatitis-B is crucial during early childhood in a country like India where maternal screening of hepatitis-B surface antigen is almost negligible and there is a considerable risk of vertical transmission among children. It is also evident that coverage of hepatitis-B is lowest among all other vaccine doses included in the universal immunization program. In addition, the major challenge is posed by the missed and drop-out of different doses of hepatitis-B among Indian children. In this context, this study examined the population and sub-national level diversity in missed and dropout of different doses of hepatitis-B vaccine in India. We analysed a large dataset of 196,654 children aged 12-59 months from a nationally representative cross-sectional survey, the National Family Health Survey (NFHS), 2015-16. Bivariate cross tabulation was used to estimate the prevalence and the dropout rates. Multivariable-adjusted logistic regression was applied to assess the likelihood of the study events. Within a Bayesian framework, a district-level spatial analysis was conducted employing the Besag-York-Mollie (BYM) Model and the Leroux Model. During 2016, 38% of the children missed the birth dose nationally and 45% of the children did not complete full immunization of hepatitis-B. Findings suggest, presence of socio-economic and demographic gradients in missed and drop-out of different doses of hepatitis-B at national level. The sub-national level spatial analysis identifies more than 280 (out of 640) districts with substantially higher risk (Posterior Median Risk>1) in terms of missed and drop-out of different doses. Most of these districts are scattered across the North-Eastern and Northern part of India. The findings hint the existence of a population and sub-national level diversity in India's missed out and dropout of hepatitis-B doses. Identifying high risk population sub-groups and the districts with children at higher risk of missing the birth and consecutive doses informs the existing knowledge base and helps in formulating community-oriented policies and programs.