10.2.1 How to measure immunization coverage rates
Immunization coverage is the percentage of eligible fully-immunized infants compared to the total number of surviving infants in the target population. 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. The equation below shows you how to calculate immunization coverage rate in your kebele.
Immunization coverage rate (for a particular vaccine) =
number receiving all doses ÷ number in the target population x 100%, where:
- number receiving all doses is the number of surviving infants under one year of age receiving all the required doses during the previous 12 months for the selected vaccine.
- target population is the total number of eligible infants under one year of age (or total number of surviving infants) at the start of that reporting period.
If the total number of fully immunized infants aged under one year in a particular kebele was 192 during the annual reporting period, and the total number of eligible infants in this age group was 205, what was the immunization coverage rate in that period?
The calculation is (192 ÷ 205) x 100% = 93.6%. In other words, in this example, 93.6% of the eligible infants were fully immunized during that reporting period.
If the number of fully immunized infants appears to be greater than the number in the target population, this indicates that some of the recorded information must be incorrect. The reason for this problem should be identified.
Can you suggest some possible reasons for this problem with the coverage data?
The target population data may be incorrect; there could have been more surviving infants aged under one year than the number counted. The number of fully immunized infants recorded may include some children aged over one year. Children from other areas (not counted in your target population) may have come to your Health Post for immunization.