2023-03-14-世界卫生组织-Updated_working_definitions_and_primary_actions_for_SARS-CoV-2_variants_4页_200kb

SARS-CoV-2 Variant Classification and Actions Update (WHO, 15 March 2023)

Updated Date: 15 March 2023
Context: SARS-CoV-2 viruses evolve over time, with some changes potentially affecting spread, severity, vaccines, or diagnostics. WHO began assigning Greek letters to variants of concern (VOCs) and variants of interest (VOIs) in May 2021 but now only uses Greek letters for VOCs; VOIs are referred to using Nextstrain or Pango nomenclature (e.g., XBB.1.5/23A). WHO and its Technical Advisory Group on Virus Evolution (TAG-VE) perform regular risk assessments.

Key Changes:

• Greek letters are now only allocated to VOCs.
• VOIs use established scientific naming systems like Nextstrain and Pango.
• Enhanced monitoring and re-assessment for variants with uncertain impacts.

Variant Definitions (Updated 15 March 2023):

• Variant Under Monitoring (VUM): A variant with genetic changes suspected to affect virus characteristics and early growth advantage, but evidence of phenotypic or epidemiological impact is unclear; requires enhanced monitoring.
• Variant of Interest (VOI): A variant with genetic changes that may affect transmissibility, virulence, antibody evasion, or therapeutic susceptibility; identified with growth advantage in multiple WHO regions or other emerging risks.
• Variant of Concern (VOC): A VOI that meets risk assessment criteria, potentially increasing severe disease risk, significantly impacting health systems, or reducing vaccine effectiveness.

Primary Actions by WHO:

• VUM: Review global epidemiology and monitor spread.
• VOI: Review epidemiology, monitor spread, comparative risk assessment, facilitate virus sharing via WHO Biohub, and coordinate laboratory investigations if needed.
• VOC: Conduct comparative assessment, communicate findings, evaluate guidelines, facilitate virus sharing, and coordinate with Member States.

Primary Actions by Member States:

• VUM: Inform WHO, submit genome sequences to public databases like GISAID.
• VOI: Inform WHO with case details, submit sequences, perform field and laboratory assessments, and share virus isolates.
• VOC: Submit sequences to GISAID, report cases to WHO via IHR, share isolates, and conduct field/laboratory investigations if capacity allows.