SARS-CoV-2 Virus (COVID-19) Variants

SARS-CoV-2 Virus (COVID-19) Variants
SARS-CoV-2 Virus (COVID-19) Variants
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The constantly mutating SARS-CoV-2 virus has many variants, which differ from one another in terms of transmission, disease severity, and pathogenicity. And some are more of a concern to the general public than others.
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What Are the CDC’s 4 Categories of SARS-CoV-2 Virus Variants?

The SARS-CoV-2 virus, like all viruses, is constantly changing through genetic mutations that lead to the emergence of new SARS-CoV-2 variants. A variant is a viral genome (genetic code) that may contain one or more mutations. The U.S. Department of Health and Human Services (HHS) established a SARS-CoV-2 Interagency Group (SIG) that meets regularly to assess the risks posed by SARS-CoV-2 variants circulating in the U.S. They divided SARS-CoV-2 variants into four categories, shown as follows: 

1.) Variant being monitored (VBM)

A variant being monitored is a variant that may have a potential impact on authorized medical countermeasures or a variant associated with more severe disease or increased transmission.

2.) Variant of interest (VOI)

A variant of interest may have specific genetic markers or mutations associated with changes in how the virus behaves, or laboratory studies may suggest that the variant has some potentially relevant features that have not been studied or documented in humans.

3.) Variant of concern (VOC)

A variant of concern is a variant that is evidenced to be able to increase transmissibility, cause more severe disease (increased hospitalization or death), reduce the effectiveness of treatments or vaccines, reduce protection from previous SARS-CoV-2 infection, or result in reduced sensitivity of diagnostic tests mutations.

4.) Variant of high consequence (VOHC)

High-consequence variants have clear evidence that the effectiveness of preventive measures or medical countermeasures (MCMs) is significantly reduced compared to previously prevalent variants.
Since the effects of variants can vary by location, the U.S. classification may differ from the World Health Organization (WHO) classification. In order to facilitate public discussion and understanding of these variants, the WHO recommends the use of Greek letters (e.g. Alpha) to name important variants. These variants are classified into “variants of concern” (VOCs) and “variants of interest” (VOIs) according to their respective transmission and pathogenicity. 

VOI variants must meet one of the following two conditions:

1.) compared with a reference variant, the mutation of the variant’s genome causes a change in the phenotype of the virus, or 2.) the variant causes community transmission or spreads in multiple countries and regions. Epsilon and Zeta are examples of previous VOIs, and there’s no circulating VOI at present.
Keren Wang
Keren Wang
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