2022-01-30-世界卫生组织-Corrigenda_for_the_WHO_SAGE_Roadmap_for_prioritizing_uses_of_COVID-19_vaccines_4页_199kb

WHO SAGE Roadmap for Prioritizing Uses of COVID-19 Vaccines Summary

Core Content

The WHO SAGE (Strategic Advisory Group of Experts) roadmap for prioritizing the use of COVID-19 vaccines outlines an approach to optimize global vaccine impact based on public health goals, global and national equity, and vaccine access and coverage scenarios. It was first issued on 20 October 2020 and has been updated multiple times, with the latest update on 21 January 2022.

Key Principles and Framework

• Priority-use Groups: The primary determinant for assigning a subgroup to a priority-use group is the risk of severe disease and death. This aligns with the human well-being principle in the WHO SAGE values framework. Other considerations include reducing societal and economic disruption, protecting essential health services, and ensuring national equity and reciprocity.
• Vaccine Coverage Rates: Coverage rates for very high and high priority groups are not fixed due to varying national capacities. General guidance suggests very high coverage (above 70%) and low coverage (below 10%) as thresholds. These rates are used to evaluate vaccine distribution effectiveness.
• Equity and Transparency: WHO emphasizes that prioritization decisions must be transparent and free from conflicts of interest, corruption, or privilege. Decision-makers must be able to justify their choices publicly and reasonably.

Vaccination Schedules

• Homologous Schedules: Standard practice for both primary series and booster doses, based on safety, immunogenicity, and efficacy data.
• Heterologous Schedules: Increasing evidence suggests that heterologous (non-matching) vaccination schedules may offer superior immunogenicity for some vaccines. WHO supports a flexible approach and considers two doses of any EUL (WHO Emergency Use Listing) vaccine as sufficient for completing the primary series.
• Implementation Considerations: Heterologous schedules should be implemented only after careful assessment of vaccine supply, projections, and the potential benefits and risks of the specific vaccines used.

Public Health and Social Measures

• Continuation of Measures: Despite vaccine availability, public health and social measures (e.g., face masks, physical distancing, handwashing) remain essential due to the modest impact of vaccines on transmission, especially with the Omicron variant.
• School Strategies: Countries should design strategies to facilitate children's participation in education and social activities, even if they are not vaccinated. UNICEF and WHO have provided guidance on minimizing transmission in schools and keeping them open.

Variants and Vaccine Efficacy

• Delta and Omicron Variants: Vaccine effectiveness against asymptomatic infection and transmission is reduced for Delta and Omicron variants. While effectiveness against severe disease remains relatively high, the potential for indirect protection (e.g., through reducing transmission in younger groups) is limited.
• Ongoing Research: The roadmap acknowledges the need for updated information on vaccine impact on transmission and indirect protection, and this advice will be revised accordingly.

Updates and References

• The scenarios have been updated to reflect current epidemiology, transmission patterns, variants of concern, and population-level immunity.
• References have been revised to include updated sources, such as WHO's considerations for public health and social measures and the Framework for Reopening Schools by UNESCO, UNICEF, World Bank, World Food Programme, and UNHCR.

Conclusion

The WHO SAGE roadmap emphasizes a balanced approach to vaccine prioritization, considering both health outcomes and broader societal impacts. It advocates for flexibility in vaccination schedules, transparency in decision-making, and the continued use of public health measures to control the spread of SARS-CoV-2, especially in the face of emerging variants.