Immunization coverage among 1-year-olds
- with one dose of measles vaccine (percentage)
- with three doses of diphtheria, tetanus toxoid and pertussis (DTP3) vaccine (percentage)
- with three doses of hepatitis B (HepB3 ) vaccine(percentage)
- with three doses of Haemophilus influenzae type B vaccine (Hib3) vaccine (percentage)
- Neonates protected at birth against neonatal tetanus (PAB) (percentage)
Rationale for use
Immunization coverage estimates are used to monitor immunization services and to guide disease eradication and elimination efforts, and are a good indicator of health system performance.
Definition
Measles immunization coverage is the percentage of one-year-olds who have received at least one dose of measles-containing vaccine in a given year. For countries recommending the first dose of measles vaccine in children over 12 months of age, the indicator is calculated as the proportion of children less than 24 months of age receiving one dose of measles-containing vaccine.
DTP3 immunization coverage is the percentage of one-year-olds who have received three doses of the combined diphtheria, tetanus toxoid and pertussis vaccine in a given year.
HepB3 immunization coverage is the percentage of one-year-olds who have received three doses of hepatitis B3 vaccine in a given year.
Hib3 immunization coverage is the percentage of one-year-olds who have received three doses of Haemophilus influenzae type B vaccine in a given year.
PAB is the proportion of neonates in a given year that can be considered as having been protected against tetanus as a result of maternal immunization.
Data sources
Administrative data: Reports of vaccinations performed by service providers are used for estimates based on administrative data service providers (e.g. district health centres, vaccination teams, physicians). The estimate of immunization coverage is derived by dividing the total number of vaccinations given by the number of children in the target population, often based on census projections.
Household surveys: Survey items correspond to children’s history in coverage surveys. The principle types of surveys are the Expanded Programme on Immunization (EPI) 30-cluster survey, the UNICEF Multiple Indicator Cluster Survey (MICS), and the Demographic and Health Survey (DHS).
Methods of estimation
WHO and UNICEF rely on reports from national public health authorities, household surveys, and other sources and have developed a joint review and estimation process. Draft estimates are review by national authorities and external experts prior to finalization.
Disaggregation
National estimates have been available since 1980. No age, sex, location (urban/rural, subnational administrative areas) or socioeconomic characteristics are available.
References
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WHO vaccine-preventable diseases: monitoring system. 2007 global summary.
Geneva, World Health Organization, 2007 (document WHO/IVB/2007) -
Immunization summary: the 2007 edition. A statistical reference containing data through 2005.
New York, United Nations Children’s Fund, 2007
Database
- WHO and UNICEF estimates of national immunization coverage
- WHO UNICEF estimates on immunization coverage 1980–2006
Comments
The principal challenges are to improve the quality (accuracy, validity, completeness and timeliness) of the data. Also, interpretation of available data needs to be improved by adjusting for possible biases, so as to obtain the most accurate estimate of immunization coverage possible.