New Covid strain renamed ‘Omicron’
- The World Health Organization (WHO) has declared a new coronavirus variant and named it Omicron.
- WHO has designated B. 1.1.529 (Omicron) as a variant of concern.
- Variant has a large number of mutations, some of which are concerning.
New Covid Variant
- B.1.1.529 strain of COVID-19, first detected in southern Africa.
- The classification puts Omicron into the most-troubling category of COVID-19 variants, along with the globally-dominant Delta.
- The epidemiological situation in South Africa has been characterized by three distinct peaks in reported cases, the latest of which was predominantly the Delta variant.
- The WHO takes several weeks to complete studies of Omicron to see if there are any changes in transmissibility, severity or implications for COVID-19 vaccines, tests and treatments.
- The change in classification came after a quickly-assembled virtual meeting of the WHO’s Technical Advisory Group on SARS-CoV-2 Virus Evolution.
- Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs.
- The Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE) is an independent group of experts that periodically monitors and evaluates the evolution of SARS-CoV-2.
- It assesses if specific mutations and combinations of mutations alter the behaviour of the virus.
- The TAG-VE was convened to assess the SARS-CoV-2 variant: B.1.1.529.
How Variants Are Classified
- Each variant classification includes the possible attributes of lower classes (e.g., VOC includes the possible attributes of VOI); variant status might escalate or deescalate based on emerging scientific evidence.
- Apart from US Classification, WHO also classifieds the different variants of Coronaviruses based on VOC and VOI.
- WHO uses the Greek Alphabet to classify different Coronaviruses variants such as Alpha, Beta, Gamma, as a practical way to discuss variants.
Variant of Interest (VOI)
- A variant with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity.
Possible attributes of a variant of interest:
- Specific genetic markers that are predicted to affect transmission, diagnostics, therapeutics, or immune escape.
- Evidence that it is the cause of an increased proportion of cases or unique outbreak clusters.
- Limited prevalence or expansion in the US or in other countries.
Variant of Concern (VOC)
- A variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.
Possible attributes of a variant of concern:
- Evidence of impact on diagnostics, treatments, or vaccines.
- Evidence of increased transmissibility.
- Evidence of increased disease severity.
Variant of High Consequence (VOHC)
- A variant of high consequence has clear evidence that prevention measures or medical countermeasures (MCMs) have significantly reduced effectiveness relative to previously circulating variants.
Possible attributes of a variant of high consequence:
- Impact on Medical Countermeasures (MCM)
- Demonstrated failure of diagnostic test targets
- Evidence to suggest a significant reduction in vaccine effectiveness, a disproportionately high number of infections in vaccinated persons, or very low * Vaccine-induced protection against severe disease
- Significantly reduced susceptibility to multiple Emergency Use Authorization (EUA) or approved therapeutics
- More severe clinical disease and increased hospitalizations