All viruses - including SARS-CoV-2, the virus that causes Covid-19 - evolve over time. When a virus is widely circulating in a population and causing many infections, the likelihood of the virus mutating increases. The more opportunities a virus has to spread, the more it replicates - and the more opportunities it has to undergo changes.
The
following are some notable coronavirus variants:-
B.1.1.7 (Alpha): This variant was first detected in the United States in December 2020.
It was initially detected in the United Kingdom.
B.1.351 (Beta): This variant was first detected in the United States at the end of
January 2021. It was initially detected in South Africa in December 2020.
P.1 (Gamma): This variant was first detected in the United States in January 2021.
P.1 was initially identified in travellers from Brazil, who were tested during
routine screening at an airport in Japan, in early January.
B.1.617.2 (Delta): This variant was first detected in the United States in March
2021. It was initially identified in India in December 2020
Lambda variant was first identified in Peru, South America.
It was designated as 'variant of interest' by the World Health Organization on
June 14, 2021.
The
World Health Organization has also listed Eta
(B.1.525), Iota (B.1.526) and Kappa
(B.1.617.1) as other variants
of interest.
More studies are needed to assess the effectiveness of the current Covid vaccines against the new variants. A growing body of data suggests that most vaccines stimulate enough immunity to retain substantial efficacy against most variants, especially against the severity of the disease, hospitalization, and death. The outcome of the more potent variants on fully vaccinated people may result in a milder form of the disease but the likelihood of not contracting the disease is slim.
The delta variant, which was first identified in India, is now the dominant form of the virus in the world. Moreover, the delta variant is more transmissible than the previous ones and it is more likely to lead to treatment in the hospital for unvaccinated patients. Yet recent data does indicate that vaccines are effective at preventing severe Covid-19 infections caused by the delta variant that would otherwise require hospital treatment.
The reason for the vaccines to substantially retain protection against the disease is likely related to the broad immune response they induce, which means that virus changes or mutations are unlikely to make vaccines completely ineffective. If any of these vaccines become less effective against one or more variants, it will likely be possible to change the composition of the vaccines to protect against these variants.
Data continues to be collected and is being analysed on the new variants of the Covid-19 virus. The World Health Organization is working with researchers, health officials and scientists to understand how these variants affect the virus’s behaviour, including their impact on the effectiveness of the vaccines. This is an area where the evidence remains preliminary but is developing quickly.
Everything
possible should be done to stop the spread of the virus in order to prevent
mutations that may reduce the efficacy of the existing
vaccines. This means staying at least one metre away from others,
covering a cough or sneezing in your elbow, frequently washing your hands,
wearing a face mask and avoiding crowded, poorly ventilated rooms or by opening
the window.
Testing and identifying those who are infectious, being able to provide them supportive isolation, tracking and contact tracing, and quarantining all the contacts can definitely make a difference in bringing down transmission.
In addition, the manufacturers and the programmes of the vaccines may have to adjust to the evolution of the Covid-19 virus: for example, vaccines may need to incorporate more than one strain when in their development, booster shots may be required, and other vaccine changes may be needed. Trials must also be designed and maintained to allow any changes in efficacy to be assessed, and must be of sufficient scale and diversity to enable clear interpretation of results. Studies of the impact of vaccines as they are deployed are also essential in order to understand their impact.
The potential of the variants to escape naturally induced and vaccine-induced immunity makes the development of next-generation vaccines that elicit broadly neutralizing activity against current and potential future variants a priority. The suppression of viral replication with both public health measures and the equitable distribution of vaccines is critical in reducing the risk of new generation of variants.
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