Immunization Coverage and Dropout Rates Under the Universal Immunization Programme: A Systematic Review and Meta-Analysis

Background: Immunization is a cornerstone of child survival strategies and a key component of public health systems worldwide. India’s Universal Immunization Programme (UIP), one of the largest vaccination programmes globally, aims to provide free vaccination against multiple vaccine-preventable diseases to all eligible children and pregnant women. Despite improvements in vaccine availability and programme strengthening initiatives, incomplete immunization and dropout between successive vaccine doses continue to challenge programme effectiveness and equity.

Objective: To systematically review and meta-analyse available evidence on immunization coverage and dropout rates under the Universal Immunization Programme in India.

Methods: A systematic review and meta-analysis was conducted following PRISMA guidelines. Electronic databases including PubMed, Scopus, Web of Science, Embase, and Google Scholar were searched for studies published between 2000 and 2025 reporting immunization coverage and/or dropout rates among children aged 0–59 months in India. Eligible observational and interventional studies were included. Data extraction and quality assessment were performed independently by two reviewers. Random-effects meta-analysis was used to estimate pooled full immunization coverage and dropout rates, and heterogeneity was assessed using the I² statistic.

Results: Twenty-eight studies comprising more than 145,000 children were included in the analysis. The pooled full immunization coverage among children aged 12–23 months was 74.8% (95% CI: 70.1–79.3). The pooled dropout rate between DPT1 and DPT3 was 12.6% (95% CI: 9.4–15.8), while the BCG–measles dropout rate was 16.9% (95% CI: 12.8–20.9). Rural, tribal, and urban-slum populations demonstrated lower coverage and higher dropout. Key determinants of incomplete immunization included low maternal education, socioeconomic disadvantage, home delivery, migration, and limited awareness of vaccination schedules.

Conclusion: Although initiation of vaccination under UIP is high, completion of the immunization schedule remains suboptimal due to persistent dropout and inequities. Strengthening routine immunization services, improving caregiver awareness, implementing digital tracking systems, and targeting high-risk populations are essential to achieve equitable universal immunization coverage