Background: Low birth weight (LBW) infants constitute a vulnerable subset of infants with impaired immunity in early life. In India, there is scarcity of studies that focus on immunization practices in such infants. This analysis aimed to examine immunization practices in LBW infants with the intention to identify areas requiring intervention.
Methods: Data on immunization status of LBW infants enrolled in an individually randomized, double-masked, placebo-controlled trial of neonatal vitamin A supplementation were analysed. Study outcomes were full immunization by one year of age and delayed vaccination with DPT1 and DPT3. Multivariable logistic regression was performed to identify factors associated with the outcome(s).
Findings: Out of 10 644 LBW infants enrolled in trial, immunization data were available for 10 517 (98.8%). Less than one-third (29.7%) were fully immunized by one year of age. Lowest wealth quintile (adjusted odds ratio (AOR) 0.39, 95% confidence interval (CI) 0.32-0.47), Muslim religion (AOR 0.41, 95% CI 0.35-0.48) and age of mother <20 years (AOR 0.62, 95% CI 0.52-0.73) were associated with decreased odds of full immunization. Proportion of infants with delayed vaccination for DPT1 and DPT3 were 52% and 81% respectively. Lowest wealth quintiles (AOR 1.51, 95% CI 1.25-1.82), Muslim religion (AOR 1.41, 95% CI 1.21-1.65), mother aged <20 years (AOR 1.31, 95% CI 1.11-1.53) and birth weight <2000 g (AOR 1.20, 95% CI 1.03-1.40) were associated with higher odds of delayed vaccination for DPT-1. Maternal education (≥12 years of schooling) was associated with high odds of full immunization (AOR 2.39, 95% CI 1.97-2.91) and low odds of delayed vaccination for both DPT-1 (AOR 0.59, 95% CI 0.49-0.73) and DPT-3 (AOR 0.57, 95% CI 0.43-0.76).
Conclusion: In this population, LBW infants are at a risk of delayed and incomplete immunization and therefore need attention. The risks are even higher in identified subgroups that should specifically be targeted.