Photographer: Matthew Horwood / Getty Images
Photographer: Matthew Horwood / Getty Images
Viruses move all the time, including the new coronavirus that caused the global pandemic. But a variant that appeared in the south-east of England in September caused great concern, leading to an emergency. blockade in London for Christmas and causing countries inclusive Canada, France and Germany to stop flights and suspend rail connections.
1. Why is this mutation alarming?
Nicknamed “B.1.1.7 progeny”, the strain underwent nearly a dozen genetic changes from the virus that emerged from Wuhan, China in late 2019 – much more than commonly observed. This includes changes in key areas of the virus involved in its ability to infect humans. Preliminary analysis in the UK suggests that it could be just as much 70% more transmissible than other circulating SARS-CoV-2 strains and can contribute to growth in cases in the country. Maria van Kerkhove, technical leader of the World Health Organization on Covid-19, told the BBC on December 20 that the WHO was working to understand the extent to which the virus could spread more easily, along with other human behavioral factors that could lead to transmission. It also looks at whether the mutation causes more severe disease and can steal vaccine-generated antibodies.
2. What is known about when it appeared?
The two oldest 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 why the new variant proliferated was that its appearance coincided with the festive season traditionally associated with the increase of the family and social mixture. The scientists hypothesized that the strain could have resulted from the transmission of the virus from a chronically infected patient.
3. How fast did it spread?
As of 15 December, 1,623 virus samples have been identified as belonging to line B.1.1.7. Of these, 519 were collected from patients in the Greater London, 555 in Kent and 545 in other parts of the UK, including Scotland and Wales. Cases have also been identified in Denmark, Netherlands, Belgium and Australia. Just since approximately 10% of SARS-CoV-2 samples from patients in the UK undergo genetic sequencing, the number of known cases is an underestimation of the actual number of infections. Infection rates in areas where the strain has circulated have it has grown faster than expected, Public Health England said on December 20, adding that further analysis found it had a higher transmission rate than other variants in circulation. Paul Hunter, a professor of medicine at Norwich School of Medicine at the University of East Anglia, told the Science Media Center that the new variant is responsible for 62% of SARS-CoV-2 infections in London in the week ending December 9, up from 28% of infections in early November.
4. How many other mutations are there?
Viruses change constantly through mutations that occur naturally as they reproduce and circulate in their hosts. As a result of this continuous process, many thousands of mutations and distinct offspring have already appeared in the SARS-CoV-2 genome since the virus first appeared in late 2019. As mutations continue to occur, more and more new variants are found, with the vast majority of mutations having no apparent effect on the virus. . However, scientists are paying close attention to mutations such as those that have appeared in the new strain in the UK involving the gene encoding the SARS-CoV-2 peak protein, which is associated with viral entry into cells and influences immunity and efficacy. vaccine.
5. Will vaccines still be effective?
It is currently unknown to what extent SARS-CoV-2 may evolve to escape immunity induced by infection or vaccination. Studies are underway to better understand this. WHO is van Kerkhove told the BBC that current information suggests the new variant has no impact on vaccine launches. Over time, as more mutations occur, it may be necessary to modify the vaccines. This happens with the seasonal flu, which moves every year, and the vaccine is adjusted accordingly. Unlike the flu, coronaviruses have a mechanism for reading evidence that means they do not move as fast as the flu virus. Covid-19 vaccines that have so far been shown to be effective in studies may be slightly modified, if necessary, the BMJ medical journal reported on December 16.