The World Health Organization on Friday, 26 November, named the recently detected B.1.1.529 strain of COVID-19 'Omicron.' It has been named after the fifteenth letter of the Greek alphabet.
The variant, first reported in South Africa, has been declared a "variant of concern" by the WHO.
How does a virus mutate? On what basis are variants classified as Variants of Concern? Here's a primer.
Why does a virus mutate? When will the COVID-19 virus stop mutating?
SARS-Cov-2 (COVID-19) virus is a single-stranded RNA virus. Mutations are changes in the genetic sequence of the RNA. They are a natural part of the virus' evolution.
When a virus enters a susceptible body, it starts replicating, and the rate of replication increases with the spread of the infection.
A virus that has a mutation in it is called a variant.
The COVID-19 virus will continue to mutate for as long as the pandemic goes on, so it is important to keep following COVID-appropriate behaviour.
What impact do mutations have?
A mutation begins to affect us when it leads to changes in transmission levels or in treatment.
Mutations can have positive, negative, or neutral impacts on human health.
A positive impact can mean that the virus becomes non-viable.
Negative impacts could be increased transmissibility, increased severity of infection, clustering of infections, ability to evade immunity and infect someone who has past immunity, neutralisation escape from monoclonal antibodies, and improved binding to lung cells.
Why does the COVID-19 virus mutate frequently?
There are a number of reasons why the virus could be mutating:
Random error during virus replication.
Immune pressure faced by viruses after treatments like vaccination, convalescent plasma, or monoclonal antibodies.
Uninterrupted transmission due to lack of COVID-appropriate behaviour. The virus becomes fitter and more transmissible as it finds excellent hosts to grow.
What is a Variant of Interest and a Variant of Concern?
If a mutation has a previous association with a similar variant, which could have an impact on public health, it becomes a Variant under Investigation.
When genetic markers, which can be associated with receptor binding domain or could have an implication on antibodies or neutralising assays are identified, it is called a Variant of Interest.
It becomes a Variant of Concern once we get evidence of increased transmission from field-site and clinical correlations.
Variants of Concern have one or more of these features:
Increased transmissibility.
Change in virulence/disease presentation.
Ability to evade diagnostics, drugs, and vaccines.
As of now, four variants of concern have been identified by scientists – Alpha, Beta, Gamma, and Delta.
Why has Omicron been classified as a Variant of Concern?
The Delta Plus has the following characteristics that make it a Variant of Concern:
Increased transmissibility.
Stronger binding to receptors of lung cells.
Potential reduction in monoclonal antibody response.
Potential post-vaccination immune escape.
Why is public health action not taken as soon as a mutation is observed in a virus?
It is not possible to determine whether the mutations will increase transmission.
We cannot confirm that there is a surge in a particular variant unless we have scientific evidence that proves a correlation between rising number of cases and variant proportion.
Once mutations are found, a week-on-week analysis is made to figure out if there is any such correlation. Finding such a correlation will help us be prepared in case the variant is seen in another region.
Public health action can be taken only after obtaining this proof.
What can I do to safeguard myself from the Variants of Concern?
We must continue to follow COVID-appropriate behaviour, such as wearing a mask, washing hands frequently, and maintaining physical distancing.
The second wave is not yet over, and it is possible to prevent a big third wave by practising protective behaviour.
Test Positivity Rate must be carefully monitored by each district, if it goes above five percent, strict restrictions must be enforced.
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