2021-12-13-世界卫生组织-Update_70_–_Update_on_SARS-CoV-2_variant_of_concern_Omicron_16页_1mb

Coronavirus Update Summary

Current Situation (As of 10 December 2021)

• Cases: Over 262 million globally since the beginning.
• Deaths: Over 5.2 million.

SARS-CoV-2 Variants

Definitions:

• Variant of Interest (VOI): Genetic changes may affect virus properties, some with potential global significance.
• Variant of Concern (VOC): VOIs that meet specific criteria for significant impact, such as increased transmissibility, severity, or reduced effectiveness of interventions.

Omicron (B.1.1.529) as a Variant of Concern:

• Designated by WHO on November 26, 2021.
• High number of mutations, especially in the spike protein, potentially increasing transmissibility and immune escape.

Key Variant Properties:

1. Transmissibility: Omicron may be more transmissible than previous variants.
2. Immune Escape: Likely reduced effectiveness of existing vaccines and past immunity.
3. Clinical Impact: Disease severity is still under study, but vaccines remain effective against severe outcomes.

WHO Expert Mechanisms

Several groups advise WHO on variant assessment and response:

• TAG-Voice (Virus Evolution)
• TAG-CO-VAC (Vaccine Composition)
• Working groups for clinical management, therapeutics, and vaccines.

Preventive and Mitigation Measures

The WHO recommends:

• Physical distance, mask-wearing, handwashing, ventilation.
• Vaccination and genomic surveillance.
• Risk-based travel policies that consider local epidemiology, immunity, and health system capacities.

International Travel

• Travel bans are discouraged due to ineffectiveness and burden.
• Countries should implement health measures based on risk assessments.

This summary highlights the emergence and risks associated with the Omicron variant and outlines WHO recommendations for monitoring, response, and prevention.