2022-07-05-世界卫生组织-Immunization_Luxembourg_2022_country_profile_16页_345kb

WHO and UNICEF National Immunization Coverage Estimates Summary

Core Content

WHO and UNICEF jointly estimate national immunization coverage to provide accurate and reliable data on vaccine uptake. These estimates are country-specific and are derived from a combination of administrative data, official reports, and survey-based information. The estimates aim to reflect the true immunization system performance, accounting for potential biases in the data.

Main Points

• Estimation Process:

  • Data is reviewed individually for each country and vaccine.
  • If no data is available, it is interpolated from neighboring years.
  • In cases of mixed data sources, the most likely estimate is chosen with consideration of possible biases.

• Types of Coverage Data:

  • Administrative coverage: Based on reports from health service providers. May be biased due to inaccurate numerator or denominator data.
  • Official coverage: Estimated by national authorities using any combination of administrative, survey-based, or other data sources.
  • Survey coverage: Derived from population-based household surveys among children aged 12-23 or 24-35 months. Based on documented evidence or caregiver recall.

• Vaccine-Specific Coverage Indicators:

  • BCG: Percentage of births who received one dose of BCG vaccine.
  • DTP1/DTP3: Percentage of surviving infants who received the 1st or 3rd dose of DTP vaccine.
  • Pol3: Percentage of surviving infants who received the 3rd dose of polio vaccine (either OPV or IPV).
  • IPV1: Percentage of surviving infants who received at least one dose of inactivated polio vaccine (IPV).
  • MCV1/MCV2: Percentage of surviving infants who received the 1st or 2nd dose of measles containing vaccine.
  • RCV1: Percentage of surviving infants who received the 1st dose of rubella-containing vaccine.
  • HepB3: Percentage of surviving infants who received the 3rd dose of hepatitis B vaccine.
  • Hib3: Percentage of surviving infants who received the 3rd dose of Haemophilus influenzae type b vaccine.
  • RotaC: Percentage of surviving infants who received the final recommended dose of rotavirus vaccine.
  • PcV3: Percentage of surviving infants who received the 3rd dose of pneumococcal conjugate vaccine.
  • YFV: Percentage of surviving infants who received one dose of yellow fever vaccine.

• Grade of Confidence (GoC):

  • Introduced in 2011 to indicate the empirical support for the estimates.
  • GoC is not a measure of data quality but reflects the degree of support from reported data, independent denominators, and supporting surveys.
  • Possible GoC categories:
    • R+: Supported by reported data.
    • D+: Supported by independent denominator.
    • S+: Supported by at least one survey within 2 years.
    • GoC=No accepted empirical data: No direct data or survey support.
  • In some years, estimates are challenged by data sources (e.g., R-), indicating potential inconsistencies or biases.

Key Information

• Estimates for 2010-2021:

  • For most vaccines, coverage estimates range from 96% to 99% across the years.
  • 2010 and 2015 had high coverage supported by surveys (99% and 100%, respectively).
  • 2019 had estimates based on interpolation and was marked with GoC=No accepted empirical data.
  • 2021 had coverage estimates based on national government reports, with GoC=R+.
  • Official coverage for most years is 100%, except for 2019 and 2021, where it was NA or 99% respectively.

• Methodological Notes:

  • No classical confidence intervals are provided due to the absence of a probability model.
  • Subjective plausibility ranges are not used.
  • Coverage data is not always accurate and may be influenced by reporting practices and biases.

• Disclaimer:

  • WHO and UNICEF take reasonable precautions to verify the data but do not guarantee its accuracy.
  • The responsibility for interpreting and using the data lies with the reader.
  • Estimates should be used with caution and evaluated based on their intended purpose.

Summary Table