Viruses are continually changing and mutating itself. Every time a virus replicates (makes copies of itself), it has the capacity to modify its structure. Each of these modifications is referred as a "mutation." A virus that has undergone one or more mutations is referred as a "variant" of the original virus.
Some mutations can induce changes in critical properties of the virus, such as those that impact its capacity to propagate and/or cause more severe sickness and death.
This leads to the development of different strains and variants of the same virus.
1. Variants Being Monitored:
The CDC(Centres for Disease Control and Prevention) keeps track of all variations around. VBM variants are those in which evidence suggests a possible or evident influence on approved or permitted medical counter measures, or that have been associated with more severe illness or greater transmission but are no longer detectable, or are circulating at extremely low levels. These variations do not constitute a serious or imminent risk to public health.
WHO label
Pango lineage
Alpha
B.1.1.7 and Q lineages
Beta
B.1.351 and descendent lineages
Gamma
P.1and descendent lineages
Epsilon
B.1.427
B.1.429Eta
B.1.525
Lota
B.1.526
Kappa
B.1.617.1
N/A
B.1.617.3
Zeta
P.2
Mu
B.1.621, B.1.621.1
2. Variant of Interest (VOI)
A variant with specific genetic markers that has been linked to changes in receptor binding, decreased neutralisation by antibodies generated in response to previous infection or vaccination, decreased treatment efficacy, potential diagnostic impact, or predicted increase in transmissibility or disease severity is variant of intrest.
Properties of a variant of interest:
· Specific genetic markers predicted to influence transmission, diagnosis, treatment, or immunity avoidance.
· The evidence is that it causes an increase in the incidence of single cases or clusters. .
A Variant of Curiosity or interest may necessitate one or more suitable public health actions, such as increased sequence surveillance, improved laboratory characterization, or epidemiological investigations to determine the ease with which the virus spreads to others, the severity of disease, therapeutic efficacy, and whether currently approved or authorised vaccines provide protection.
3. Variant of Concern (VOC)
A variant with evidence of increased transmissibility, more severe disease (for example, increased hospitalizations or deaths), significant reduction in neutralisation by antibodies generated during previous infection or vaccination, decreased effectiveness of treatments or vaccines, or diagnostic detection failures is variant of concern.
In addition to the potential characteristics of a variation of interest
· Evidence of a positive influence on diagnostics, treatments, or vaccinations
i) Interference with diagnostic test targets is widespread.
ii) Evidence of significant reduction of susceptibility to one or more classes of therapy
iii) Evidence of considerably reduced neutralisation by antibodies produced during previous illness or vaccination.
iv) Evidence of diminished vaccine-induced protection against severe disease Evidence of heightened transmissibility
· There is evidence of increasing disease severity.
Variants of interest may require one or more appropriate public health actions, such as notification to WHO under International Health Regulations, notification to CDC, local or regional efforts to control the spread, increase testing or research to determine the effectiveness of vaccines and treatments against variants. Based on variant characteristics, additional considerations may include developing new diagnoses or modifying vaccines or treatments.
Variants of current interest in the United States are being closely watched and have the characteristics listed below. This table will be updated when a new variant of interest is identified.
SARS-CoV-2 Variant Characteristics:
WHO Label: Delta
Pango Lineage: B.1.617.2 and AY lineages (Pango lineage)
Spike Protein Substitutions: T19R, (V70F*), T95I, G142D, E156-, F157-, R158G, (A222V*), (W258L*), (K417N*), L452R, T478K, D614G, P681R, D950N
Nextstrain clade (Nextstrain)b: 21A/S:478K
First Identified: India
Features :
• Higher transmissibility
• Nearly all Delta lineages are amenable to Emergency Use Authorization (EUA) monoclonal antibody therapies. Some monoclonal antibody therapies are ineffective against the AY.1 and AY.2 lineages.
• Less neutralisation by post-vaccination sera
Note:
(*) = detected in some sequences but not all
a - Phylogenetic Assignment of Named Global Outbreak (PANGO) Lineages is a software tool created by Rambaut Lab members. The accompanying online application was created by the Centre for Genomic Pathogen Surveillance in South Cambridgeshire and is designed to incorporate the PANGO nomenclature for SARS-CoV-2 lineages.
b – Nextstrain, a cooperation between academics in Seattle, Washington, and Basel, Switzerland, offers open-source tools for visualising epidemic genetics. The objective is to aid public health surveillance by improving understanding of disease distribution and evolution.
WHO Label: Omicron
Pango Lineage: B.1.1.529 and BA lineages (Pango lineage)
Spike Protein Substitutions: A67V, del69-70, T95I, del142-144, Y145D, del211, L212I, ins214EPE, G339D, S371L, S373P, S375F, K417N, N440K, G446S, S477N, T478K, E484A, Q493R, G496S, Q498R, N501Y, Y505H, T547K, D614G, H655Y, N679K, P681H, N764K, D796Y, N856K, Q954H, N969K, L981F
Nextstrain clade (Nextstrain) 21K
First Identified: South Africa
Features:
• Possibility of enhanced transmissibility
• Possibility of reduced neutralisation by various EUA monoclonal antibody therapies
• Possibility of reduced neutralisation by post-vaccination sera
4. Variant of High Consequence (VOHC)
A VOHC contains clear proof that preventive measures or medical countermeasures (MCMs) are much less effective than previously circulating versions.
A high-impact variety would necessitate notice to WHO under the International Health Regulations, reporting to the CDC, the announcement of prevention or containment initiatives, and recommendations to update treatments and immunizations.
Discussion about Omricon:
As of December 1, 2021, there is little known about Omicron. Studies are being conducted to see whether there is a difference in how quickly the virus spreads or the severity of the sickness it causes, as well as any implications for preventative measures.
It will most likely take time to ascertain whether there is a difference in Omicron transmission compared to other variations, how the variant reacts to known therapies, or whether infection or re-infection with Omicron produces more or less severe illness.
WHO is collaborating with technical partners to better understand the possible influence of omicron on vaccination efficacy. The Delta form is currently widespread globally, and COVID-19 vaccinations are very effective at protecting you from serious disease and death, including Delta illness. Researchers will evaluate the efficacy of existing vaccinations against Omicron and report their findings as soon as they are available.
Sunday, February 13, 2022
Are we safe with so many more covid variants!
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Are we safe with so many more covid variants!
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