2022-07-05-世界卫生组织-Immunization_Iceland_2022_country_profile_16页_355kb

WHO and UNICEF National Immunization Coverage Estimates Summary

Core Content Overview

The document provides a detailed overview of the methodology and data sources used by the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) to estimate national immunization coverage for various vaccines. These estimates are intended to reflect the most likely immunization coverage levels in different countries, based on empirical data, while acknowledging potential biases and data quality issues.

Main Vaccines and Coverage Definitions

Methodology and Confidence Levels

• Estimates are country-specific and not borrowed from other countries in the absence of data.
• Data Sources:
  • Administrative: Reported by national authorities using aggregated data from health service providers.
  • Official: Estimated coverage based on national authorities' assessments, which may include administrative, survey, or other data.
  • Survey: Based on population-based household surveys of children aged 12-23 or 24-35 months, with vaccination history verified through documented evidence or caregiver recall.
• Grade of Confidence (GoC):
  • Reflects the degree of empirical support for the estimate, not the quality of data reported by national authorities.
  • GoC = R+ D+ S+: Well-supported by reported data, independent denominator, and at least one supporting survey within 2 years.
  • GoC = R+ D+: Supported by at least one data source (reported data, independent denominator) but no supporting survey within 2 years.
  • GoC = R- / D- / S-: Data from at least one source challenges the estimate.
  • GoC = No support: No directly supporting data, or data from at least one source challenges the estimate.
• No classical uncertainty measures (e.g., confidence intervals) are presented due to the absence of a probability model.
• Estimates are not subjective and avoid plausibility/certainty ranges.

Coverage Trends and Notes

• GoC Trends: For all years from 2010 to 2021, the GoC is consistently marked as ●●, indicating high confidence based on empirical support.
• Administrative Data: In some years, administrative data is reported (e.g., 2018, 2017, etc.), but it is often marked as NA or with lower confidence.
• Survey Data: Survey data is not available for most years and vaccines, except in a few instances.
• Improvements in Data Quality: From 2013 onwards, the reported coverage for most antigens has increased due to improved recording systems.
• Iceland Note: The use of birth cohort data in Iceland may result in minimum coverage estimates due to incomplete recording.

Key Information

• Estimates are based on multiple data sources, including administrative, survey, and independent population data.
• No data means no estimate is generated for that country/vaccine/year combination.
• Interpolation is used when data is missing for certain years.
• GoC is not a measure of data quality, but rather the degree of empirical support.
• Recommendations: WHO and UNICEF recommend independent empirical assessments to confirm reported coverage levels, especially in the absence of surveys.
• Note on IPV: Coverage for inactivated polio vaccine (IPV) began in 2015 as part of global strategies to combat polio resurgence. However, for the purpose of this document, Pol3 is still used as the main coverage metric for polio.

Disclaimer

• The information provided is based on data of varying quality and is subject to potential inaccuracies.
• No warranty is given for the accuracy of the data or the estimates.
• The responsibility for interpretation and use lies with the reader.
• Estimates should be used with caution and assessed based on the specific objective.