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Vaccination coverage, as well as most of the remaining indicators, are expressed as a prevalence or proportion. Vaccination coverage has the added complexity of having several potential sources of data, including vaccination or child heath card documentation and mother's report. If a large proportion of vaccinated children are defined as vaccinated based on only the mothers' report, vaccine coverage is calculated twice: once counting these children as vaccinated and once counting them as unvaccinated. This can be done by presenting the vaccinated children in two groups: one whose vaccination data came from a card and one who vaccination data came from mother's recall.
Bardera, Somalia 1993
|Source of data on measles vaccination||Number||Percent|
In this situation, if only children with card documentation of ever having been vaccinated against measles is used, the measles vaccine coverage is very poor (8.5%). If mothers' reports are added in, the coverage rises somewhat, but is still only 47.1%. Either way, measles vaccination is badly needed in this population.
The incidence rate of vaccine-preventable diseases can be displayed as above for morbidity indicators (click here to go to pages on morbidity indicators).