2022-07-05-世界卫生组织-Immunization_Guinea-Bissau_2022_country_profile_25页_426kb

Summary of WHO and UNICEF Immunization Coverage Estimates for Guinea-Bissau, 2021 Revision

Overview

• This report provides estimates of national immunization coverage in Guinea-Bissau for various vaccines, based on data up to July 7, 2022. The next revision is scheduled for July 15, 2023.
• Key vaccines covered include BCG, DTP1, DTP3, Pol3, IPV1, MCV1, MCV2, RCV1, HepB1, HepB3, Hib3, RotaC, and PCV3.
• Estimates are derived from administrative data, surveys, and interpolation, with varying data quality.

Methodology

• Estimates are country-specific and rely on:
  • Administrative data from health services.
  • Survey-based data from national surveys or household polls.
  • Interpolation when data gaps exist.
• Grade of confidence (GoC) is assigned based on data sources:
  • GoC reflects empirical support (e.g., R+ for reported administrative data; S+ for surveys).
  • No formal uncertainty intervals are provided, and no subjective judgments on data quality.
• Details are drawn from sources like national reports, program data, and global databases, with consideration to potential biases and event impacts.

Key Findings by Vaccine

• General Trends: Coverage varies by vaccine and year, often influenced by logistical issues and external factors like COVID-19. Recent years (e.g., 2021-2020) show lower or unexplained coverage due to stock-outs, civil servant strikes, and vaccination campaigns.
• BCG: Coverage ranged from 34% (low confidence) to 99% (high confidence) before significant dips.
• DTP1: Mean coverage around 90% historically, but affected by events; recent estimates are unexplained.
• DTP3/Pol3: Similar to DTP1, with fluctuations; surveys sometimes modified for recall bias.
• IPV1: Dated introduction in 2015; coverage initially low, often challenged due to stock-outs.
• MCV/MCV2/RCV1/Hep-series: Higher coverage levels noted, but confidence varies, with some periods of unexplained decreases.
• RotaC/Hib/Hep-series: Immunization coverage impacted by vaccine introduction and recording issues, with surveys providing key data post-2016.

Challenges and Factors

• Primary Issues: Data from administrative systems is often poor quality due to recording errors; surveys provide more reliable inputs but not always available.
• External Events: Stock-outs, civil unrest, and COVID-19 disruptions consistently reduced coverage and increased uncertainty.
• Grade of Confidence: Lower confidence (e.g., R-) in cases with unexplained data drops or poor data quality.

Implications

• Estimates should be used cautiously, contingent on the specific context or objective, as they may be imprecise and subject to revision.
• Recommendations include improving data recording, strengthening survey use, and addressing supply chain management to enhance reliability.