Immunization coverage refers to information on the proportion of children who have received specific vaccines or are up to date with the recommended vaccine schedule. This information is essential for planning immunization programmes, identifying vulnerable groups or areas that require targeting of increased resources, assessing the acceptability of a programme, and predicting likely vaccine-preventable disease epidemics. The immunization coverage rate is measured by comparing the number of doses actually given and the number in the target population of surviving infants under one year of age (these are the eligible infants). The result is expressed as a percentage.