COVID-19 Variants of Concern
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Mohamed Riad, M.D.[2] Deekshitha Manney, M. D[3]
Overview
All viruses mutate. Mutations are mistakes that happen when the virus replicates. Every single viral replication is an opportunity to mutate. All viruses, including COVID 19 needs a host cell to replicate, because viruses have genetic material but no cytoplasm and cellular proteins to replicate on their own. So the longer a virus replicates and circulates in a population of hosts, the higher chance of a mutation. Not all mutations are significant enough to change the characteristics of virus. However, a sequence of mutations (which is more likely to happen, when the viral load in a community is very high such as in a pandemic), can lead to a change in viral characteristics and can lead to difference either in transmissibility and/or virulence. These mutations can also change the efficiency of vaccines and the viral response to treatment. One of the examples of how viral mutations can affect the efficiency of vaccine is why annual flu vaccines are required. Similar to influenza virus, SARS-CoV-2 also can mutate and in a pandemic situation, the likelihood of the mutation and emergence of variants is high. As a result of mutations occurring in COVID-19 virus, new variants of COVID-19 emerge and most of them are being tracked in the United States. The "variants of concern" refer to those COVID-19 variants with clear evidence of an increased rate of transmission, severe illness and death, marked decrease in neutralization by antibodies produced as a result of previous infection or vaccination, decreased effectiveness of vaccines or treatments, or failure of diagnostic detection.
Variants of Concern
As in all viruses, COVID-19 virus continuously undergo spontaneous mutations followed by emergence of new variants of COVID-19. Some of these variants appear then disappear; however, others persist causing global pandemic. The best way to fight against the appearance of new variants is a commitment to protective measures.
The " variants of concern" refer to those COVID-19 variants with clear evidence of an increased rate of transmission, severe illness, and death, marked decrease in neutralization by antibodies produced as a result of previous infection or vaccination, decreased effectiveness of vaccines or treatments, or failure of diagnostic detection.
1) Omicron - B.1.1.529 :
The variant was first detected in South Africa. It is designated as VoC, meaning that it can pass between people easily and evade vaccines, treatments, or other protective measures. The number of mutations this variant has is concerning, estimated to be more than 30, which could have a big influence on how this virus behaves.
It is not yet clear whether omicron makes symptoms worse or is severe than other variants like delta. It is also not clear yet how Omicron affects people compared to alpha and delta variants. Infection rates have been increasing from the first week of December-2021 and we need to see how the variant affects the world.
2) Delta - B.1.617.2 :
This variant was first identified in India in early 2020. It is twice as contagious as earlier variants and might cause more severe illness. Most affected people are the unvaccinated people for this variant. Vaccinations do provide protection against this variant.
3) Alpha (B.1.1.7) :