2024-08-31-世界卫生组织-EYE_Annual_highlights_2023_7页_784kb

Yellow Fever Vaccination and Outbreak Summary (2017-2023)

Core Content

The document outlines the progress and achievements of the Yellow Fever Initiative (YFI) and the Endgame Yellow Fever (EYE) Strategy from 2017 to 2023, focusing on vaccination campaigns, outbreak responses, and laboratory and technical developments. It highlights the scale of vaccination efforts, the impact on population immunity, and the ongoing challenges and risks in high-risk regions.

Key Statistics

• People protected against yellow fever in Africa via vaccination campaigns since 2017: 264 million
• Confirmed yellow fever cases in Africa & the Americas since 2016: 4,106
• Yellow fever outbreaks between 2017 and 2023: 56
• People protected via vaccination campaigns in Africa (2023): ~62 million
• People protected via vaccination campaigns in Latin America & the Caribbean (2023): >184,000
• Children protected via routine immunization in Africa (2023): ~17.4 million
• People protected by reactive vaccination in Africa (2023): >704,000

Vaccination Campaigns in Africa

• Niger: Protected 221,000 people via reactive vaccination campaigns (RVCs)
• Guinea: Protected ~221,000 people via RVCs combined with meningitis
• Nigeria: Protected 18.7 million people via preventive mass vaccination campaigns (PMVCs)
• Sudan: Protected ~4 million people via a catch-up campaign combined with measles
• Uganda: Protected ~9.5 million people via multi-year PMVCs, including refugees
• Central African Republic (CAR): Protected ~202,000 people via RVCs, including seasonal workers and ethnic minorities
• Democratic Republic of the Congo (DRC): Protected >29.6 million people via PMVCs combined with measles

Vaccination Campaigns in Latin America & the Caribbean

• Vaccination Week in the Americas (April) and 8 Days of Action for Vaccination (October): Multi-antigen catch-up campaigns
• Venezuela: Continuing second phase of mass vaccination campaign, acquiring 5,370,000 doses
• Country profiles: Published for 12 endemic high-risk countries in Paho-iris (English, Spanish, French, Portuguese)
• Immunity gap analyses: Conducted in Colombia and Paraguay to update vaccination plans

Laboratory and Technical Achievements

Publications

• EYE-LABS website updated with latest resources
• Laboratory manual for yellow fever completed and published in English, with French, Portuguese, and Spanish versions pending
• Operational guidance on yellow fever assays published in English, with other language editions pending
• Public report on commercial kit performance evaluations published for two IgM serology assays

New Kit Evaluations

• Applications received for second Expression of Interest for molecular RT-qPCR assays
• Three products shortlisted for evaluation, final reports expected in Q3 2024

Laboratory Assessments

• Gabon: National laboratory fully accredited for serology
• Equatorial Guinea: YFNL trained in serology testing with support from CPC RRL
• Chad, Niger, Sierra Leone: Training provided for serology and molecular testing

Capacity Building

• 72 shipments of specimens completed
• Average turnaround time for shipments: 4.7 days
• Emergency shipments: 4.76 days average turnaround time
• Preliminary total samples transported: 952 (including 465 emergency shipments)

Risk Analysis and Vaccine Allocation

• Risk assessment updated for all 27 high-risk countries
• Top-risk countries: Nigeria, Cameroon, DRC, Ghana, Uganda
• Sub-national risk analysis: Conducted in Ethiopia to support decision-making
• Vaccine supply increased: Over 97.2 million doses procured through UNICEF
• Vaccine allocation support: Provided for 2024-2025

EYE Secretariat Activities

• Mid-term evaluation report published
• Country tool developed for root cause analysis and outbreak response evaluation
• Immunity gap analysis tool created, used in Guinea, Cameroon, and Gabon
• Monitoring and Evaluation (M&E) Dashboard developed in Power BI for African high-risk countries
• Guidance published on estimating reactive campaign coverage
• Weekly epidemiological record published for 2022
• Communication workshop held in Geneva
• EYE.opS information video available in French
• Podcast episode: "Ghana: A Yellow Fever Success Story"

Outbreak Response and Acute Events

• Four vaccine requests approved by the ICG for CAR, Guinea, and Niger
• Investigation and planning started for outbreaks in Cameroon and South Sudan in December 2023
• Ongoing outbreaks: 18 in 2023, with 13 in Cameroon, 4 in CAR, and 1 in South Sudan
• Risk increase: Benin, Cameroon, Ethiopia, Liberia, South Sudan, and Togo reported higher risk
• Outbreaks near borders: South Sudan and DRC, Douala (Cameroon), Senegal and Guinea, Lagos (Nigeria)

Ongoing Risks

• Immunity gaps: ~7.2 million unvaccinated children in high-risk countries
• Risk of international spread: Persistent due to ongoing outbreaks and potential cases in key areas

Conclusion

The EYE Strategy has made significant progress in vaccination coverage, outbreak response, and laboratory capacity building across Africa and Latin America. Despite these achievements, immunity gaps and the risk of epidemics remain, necessitating continued efforts in vaccination campaigns, surveillance, and technical support.