2025-05-21-世界卫生组织-WHO_Rapid_Risk_Assessment_-_Yellow_fever,_African_Region_v.4_10页_399kb

报告摘要

Yellow Fever Risk Assessment Summary (African Region)

Date and Version: 12 February 2024, v4 (revisions from previous assessments).

Overall Risk Assessment

Regional Risk: Moderate.
Global Risk: Low.
Confidence in Information: Low.
Risk Statement: The regional risk of yellow fever (YF) outbreaks in the WHO African region remains moderate due to ongoing outbreaks, persistent immunity gaps, urban transmission risks, surveillance challenges, and the strain on response capacities from multiple health emergencies.

Key Risk Factors

Persistence of Outbreaks: Stable number of outbreaks, but increased risk in hard-to-reach and mobile populations.
Immunity Gaps: Low vaccination coverage (e.g., <80% needed for herd immunity); recent coverage includes over 145M vaccinated under the EYE Strategy.
Urban Transmission: High-risk in cities like Douala, Cameroon, due to high population density and proximity to international airports.
Surveillance and Capacity Issues: Suboptimal laboratory and sample collection capabilities, leading to potential underreporting; limited human resources and supplies.
Spread Risks: Cross-border transmission possible, especially from South Sudan bordering the Democratic Republic of the Congo and Central African Republic.
Strain on Response: Multiple competing outbreaks (e.g., measles, polio, mpox) divert resources and attention.

Risk Questions and Assessments

Risk Question	Likelihood (Regional)	Consequences	Notes
High risk for unprotected populations?	Likely	Moderate-High	Cases often affect young adults and mobile groups; urban areas pose higher spread risk.
Risk of YF spreading?	Likely	Minor-Moderate	Dependent on immunity gaps, population movements, and environmental factors; vector presence outside Africa.
Insufficient control capacities?	Likely	Minor-Moderate	Challenges include delays in investigation, confirmation, and securing vaccines; strained resources.

Recommended Actions

Immediate: Activate ERF response, support Member States for preparedness, and seek further information/repeat assessment.
Continuous: Monitor outbreaks, implement vaccination campaigns, strengthen surveillance and clinical management.
Key Recommendations:
- Vaccination: Prioritize routine and reactive campaigns; target vulnerable groups.
- Surveillance: Improve sample collection and rapid case classification.
- Capacity Building: Address shortages in labs, logistics, and human resources.
- Collaboration: Enhance cross-border coordination and resource mobilization via EYE partners.

Conclusion

Yellow fever outbreaks persist with moderate regional risk, driven by immunity gaps, urban cycles, and operational challenges. Global spread is unlikely but not ruled out if measures fail. Actions focus on prevention, surveillance, and coordinated response.

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