Vaccination and associated factors among tribal children of 1 year age in nine Indian districts: A cross-sectional study.

A relatively low proportion of children were fully vaccinated among the tribal populations. Health systems factors, mainly the outreach services and advice by the health workers, were positively and significantly associated with a child being fully vaccinated by 12 months of age. Improving outreach services is crucial to improve vaccination coverage in tribal areas, and there is a need to address the social determinants in the long run.