Inequity in childhood immunization in India: a systematic review.

BACKGROUND: Despite a reduction in disease burden of vaccine preventable diseases through childhood immunization, considerable progress needs to be made in terms of ensuring efficiency and equity of vaccination coverage.
OBJECTIVE: To conduct a systematic review to identify and explore factors associated with inequities in routine vaccination of children in India.
METHODS: Publications reporting vaccination inequity were retrieved through a systematic search of Medline and websites of the WHO, UNICEF and demographic health surveys in India. No restrictions were applied in terms of study designs. The primary outcome measure was complete vaccination or immunization defined as per the standard WHO definition.
RESULTS: There were three nationwide data sets viz. the three National Family Health Surveys (NFHS), a research study conducted by the Indian Council of Medical Research (ICMR) and a UNICEF coverage evaluation survey. In addition, several publications representing different population groups or geographic regions were available. A small number of publications were reanalyses of data from the NFHS series. There is considerable inequity in vaccination coverage in different states. Within states, traditionally poor performing states have greater inequities, although there are significant inequities even within better performing states. There are significant inequities in childhood vaccination based on various factors related to individual (gender, birth order), family (area of residence, wealth, parental education), demography (religion, caste), and the society (access to health-care, community literacy level) characteristics. Girls fare uniformly worse than boys and higher birth order infants have lower vaccination coverage. Urban infants have higher coverage than rural infants and those living in urban slums. There is an almost direct relationship between household wealth and vaccination rates. The vaccination rates are lower among infants with mothers having no or low literacy, and families with insufficient empowerment of women. Paternal literacy has an inconsistent positive relationship with infant vaccination. There is a relationship between religion and caste and childhood vaccination. Access to health services and other infrastructure, is associated with better vaccination coverage of infants. The precise impact of specific risk factors operating singly or in combination cannot be calculated from this systematic review.
CONCLUSION: This systematic review identifies and explores factors associated with inequity in childhood immunization in India; and provides information for urgent action to redress the imbalances.