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Viruses mutate all the time, including the new coronavirus that has caused the global pandemic.
But a variant that emerged in south-east England in September is causing particular concern, leading to an emergency shutdown in London over Christmas and causing countries such as Canada, France and Germany to halt flights and suspend rail links.
1. Why is this mutation alarming?
Nicknamed the “B.1.1.7 lineage,” the strain has undergone nearly a dozen genetic changes from the virus that emerged from Wuhan, China in late 2019, far more than is normally observed.
That includes changes in key areas of the virus involved in its ability to infect people. Preliminary analysis in the UK suggests that it may be up to 70% more transmissible than other circulating strains of SARS-CoV-2 and may be contributing to an increase in cases in the country.
Maria van Kerkhove, the World Health Organization technical leader on Covid-19, told the BBC on December 20 that the WHO is working to understand how easily the virus can spread, along with other factors of human behavior that may be driving transmission.
It is also looking to see if the mutation causes more serious disease and can evade the antibodies generated by vaccination.
2. What is known about when it arose?
The first two known specimens were collected in late September in London and the nearby Kent area, and cases continued to be found until early December.
One of the reasons the new variant proliferated was that its appearance coincided with the festive season traditionally associated with a greater family and social mix. Scientists have hypothesized that the strain may be the result of transmission of the virus from a chronically infected patient.
3. How fast has it spread?
As of December 15, 1,623 virus samples were identified as belonging to the B.1.1.7 lineage. Of these, 519 were obtained from patients in Greater London, 555 in Kent and 545 in other regions of the UK, including Scotland and Wales.
Cases have also been identified in Denmark, the Netherlands, Belgium and Australia. Since only about 10% of SARS-CoV-2 samples from UK patients undergo genetic sequencing, the number of known cases is an underestimate of the actual number of infections.
Infection rates in areas where the strain has been circulating have risen faster than expected, Public Health England said on December 20, adding that further analysis found it has a higher transmission rate than other circulating variants. .
Paul Hunter, professor of medicine at the University of East Anglia Norwich School of Medicine, told the Science Media Center that the new variant was responsible for 62% of SARS-CoV-2 infections in London in the week ending. December 9 onwards. 28% of infections there in early November.
4. How many other mutations are there?
Viruses constantly change through naturally-occurring mutations as they replicate and circulate in their hosts. As a result of this ongoing process, many thousands of distinct mutations and lineages have already emerged in the SARS-CoV-2 genome since the virus emerged in late 2019.
As mutations continue to emerge, more and more new variants are found, and the vast majority of mutations have no apparent effect on the virus.
However, scientists are paying more attention to mutations such as those that have occurred in the new UK strain involving the gene encoding the SARS-CoV-2 spike protein, which is associated with viral entry into cells and e influences immunity and efficacy of the vaccine.
5. Will the vaccines still be effective?
It is currently unknown to what extent SARS-CoV-2 can evolve to escape immunity induced by infection or vaccination. Studies are underway to better understand it.
The WHO’s van Kerkhove told the BBC that current information suggests that the new variant has no impact on the vaccines being rolled out. Over time, as more mutations occur, the vaccines may need to be modified.
This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly.
Unlike the flu, coronaviruses have a proofreading mechanism that means they don’t mutate as fast as the flu virus. The Covid-19 vaccines that have so far been shown to be effective in trials can easily be modified if necessary, the medical journal BMJ reported on Dec. 16.
Read: New Covid-19 Variant Identified In South Africa As Numbers Rise
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