Peer-reviewed article

Parental investment in child immunisation: the role of birth order and number of children

Saranika Sarkar · 8 Jun 2026

Abstract

Background: Immunisation of children remains an important public health challenge in India despite the implementation of the Universal Immunisation Programme. Understanding how household and child-specific factors affect children's immunisation is essential for improving immunisation coverage. In this paper, the effects of the number of children and birth order on children's immunisation in India have been examined. The number of children and birth order are two related but conceptually different aspects of families. Distinguishing between the two allows us to determine whether lower immunisation among children arises from larger families or from differences in a child's position within the sibling group, the birth order. Methods: A cross-sectional analysis of nationally representative data from the fourth round of the National Family Health Survey, conducted in 2015-16, is used for the study. Logistic regression and household fixed-effects models have been employed to examine the impact of the number of children and birth order on children's immunisation. Results: The findings reveal that immunisation increases with an increase in the number of children in a family, and this is consistent across both model specifications. In addition, a strong, negative effect of birth order on immunisation has been observed. Larger families are more likely, whereas a child of a higher birth order is less likely to achieve full immunisation. Conclusions: The study highlights the importance of the number of children and birth order in explaining immunisation outcomes in India. The empirical findings show that the number of children has a positive effect and birth order has a negative effect on full immunisation.