A new variant of SARS-CoV-2, the virus that causes Covid-19, recently emerged in the UK, causing panic around the world. Many countries, including India, have cut air links to the UK as a result. The new variant is up to 70% more transmissible than the original SARS-CoV-2 strains, making it more fearsome. But you need to understand much more about it.
How did the world find out about the new variant?
The first information on the existence of the new strain came from an analysis of Covid-19 genome data routinely available as part of an epidemiological investigation to test an unexpected increase in Covid-19 cases in south-east England. On December 14, the United Kingdom informed the World Health Organization about the new variant, which has been named SARS-CoV-2 VUI 202012/01 (Investigational Variant, Year 2020, Month 12, Variant 01).
How is it different from the Covid-19 strains that are in circulation?
The variant is defined by the presence of 17 mutations or small genetic changes. Some of these mutations influence the transmissibility of the virus. The two most important mutations are in the spike protein that the virus exploits to enter human cells. The first mutation is known as N501Y while the second is called P681H. They are important for the transmission and virulence of the virus. “These mutations have been seen independently before, but never together. Both would give the virus the ability to infect cells more efficiently and therefore show increased transmission,” explained the eminent virologist Shahid Jameel, director of the Ashoka University Trivedi School of Biosciences.
Follow DH’s coverage of the Covid-19 pandemic here
What is the effect of such genetic changes?
Preliminary reports from the UK show that this variant is 40% -70% more transmissible than circulating strains. Laboratory studies are underway to determine whether these virus variants have different biological properties or alter the efficacy of the vaccine. At present, there is insufficient information to determine whether this variant is associated with any change in clinical disease severity, antibody response, or vaccine efficacy.
Has this variant been detected in any other country?
According to the WHO, the new variant has also been identified in Australia, Denmark, Italy, Iceland and the Netherlands.
Will there be an impact on existing Covid-19 tests?
One of the mutations (technically described as the deletion at position 69/70) has been found to affect the performance of some diagnostic PCR assays that use a particular target gene. But since most PCR assays around the world use multiple genetic targets, the impact of the variant on diagnosis is not expected to be significant.
Will existing vaccines and treatments work against the new variant?
Currently, there is not enough information to determine whether this variant is associated with any change in clinical disease severity, antibody response, or vaccine efficacy. The UK authorities are conducting studies to further assess the transmissibility, severity of infection, risk of reinfection and the antibody response of this new variant. More research is required to fully understand the impact of the specific mutation on viral properties and the effectiveness of diagnostics, therapeutics, and vaccines. These investigations are complex and require time and collaboration between different research groups.
What could have triggered such changes in the genetic makeup of SARS-CoV-2?
Although it is still early, a preliminary analysis by UK scientists indicates the possibility that the mutant strain originated in an immunosuppressed patient who died 101 days after being diagnosed with Covid-19. The patient received three convalescent plasma treatments that failed to clear the infection. After each treatment with convalescent plasma, important changes were observed in the virus genome. Genetic changes occur due to selection pressure that comes from the natural evolutionary process of the virus. However, at this time it is more of a hypothesis and more research is needed to understand how the strain evolved.
.
