Effects of zero-dose vaccination status in early childhood and level of community socioeconomic development on learning attainment in preadolescence in India: a population-based cohort study

Abstract

Introduction‘Zero-dose’ children (infants who fail to receive the first dose of diphtheria-tetanus-pertussis-containing vaccine) face substantial adversity in early childhood and may be at risk of failure to thrive. To inform a new global policy, we studied the relationship between zero-dose vaccination status in early childhood and learning attainment in preadolescence, and considered whether community socioeconomic development moderated these relationships.MethodsWe constructed a population cohort from the 2019 India Human Development Survey panel dataset to study the comparative performance of zero-dose versus vaccinated children identified in wave I (2004–2005) on basic learning tests at ages 8–11 in wave II (2011–2012). The outcome was a sum of reading, writing and math scores ranging from 0 (no knowledge) to 8. We fit three linear regression models examining whether child zero-dose status predicts learning attainment: a crude model, a main effects model including all prespecified covariates, and a model including an interaction between child zero-dose status and community development level.ResultsThe analytic sample included 3781 children from 3781 households in 1699 communities, representing 18.2 million children. Predicted learning attainment scores for zero-dose children were lower than those for vaccinated children by −1.698 (95% CI −2.02 to −1.37; p<0.001) points (crude model) and −0.477 (95% CI −0.78 to −0.18; p<0.001) points (adjusted for all prespecified covariates). We found strong evidence of effect modification. The model including all prespecified correlates and an interaction predicted no effect of child zero-dose status in urban areas (p=0.830) or more developed rural villages (p=0.279), but an important effect in the least developed rural villages, where zero-dose children were expected to have test scores −0.750 (95% CI −1.15 to −0.344; p<0.001) points lower than vaccinated children.ConclusionZero-dose children living in contexts of very low socioeconomic development are at elevated risk of poor learning attainment in preadolescence.