Viruses mutate all the time, including the new coronavirus that has caused the global pandemic. But a variant that emerged in the south-east of England in September is causing special concern, causing an emergency blockade in London for Christmas and causing countries included Canada, France and Germany a stop flights and suspend rail connections.
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 in Wuhan, China in late 2019, far more than is normally observed. This includes changes in key areas of the virus involved in its ability to infect people. Preliminary analyzes in the UK suggest that it may be just as large 70% more transmissible than other circulating strains of SARS-CoV-2 and may be contributing to an increase in cases across the country. Maria van Kerkhove, technical head of the World Health Organization at Covid-19, told the BBC on 20 December that the WHO is working to understand the extent to which the virus can spread more easily, along with other human behavioral factors that can lead to transmission. It is also being studied whether the mutation causes more serious diseases and can elude antibodies generated by vaccination.
2. What is known about when it arose?
The two oldest known specimens were collected in 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 an increase in family and social mix. Scientists have hypothesized that the strain may have been the transmission of the virus from a chronically infected patient.
3. How quickly has it spread?
As of December 15, 1,623 virus samples belonging to lineage B.1.1.7 were identified. Of these, 519 were collected from patients in Greater London, 555 in Kent and 545 in other regions of the United Kingdom, including Scotland and Wales. Cases have also been identified in Denmark, the Netherlands, Belgium and Australia. From only about 10% of SARS-CoV-2 samples from British patients undergo genetic sequencing, the number of known cases is an underestimation of the actual number of infections. There are infection rates in the areas where the strain has circulated increased faster than expected, Public Health England said Dec. 20, adding that further analysis found it has a higher transmission rate than other outstanding variants. Paul Hunter, a professor of medicine at the Norwich School of Medicine at the University of East Anglia, told the Science Media Center that the new variant was responsible for 62% of SARS-CoV-2 infections in London in the week ended December 9, compared to 28% of infections in early November.
4. How many other mutations are there?
Viruses constantly change through mutations that arise naturally as they replicate and circulate through their hosts. As a result of this ongoing process, many thousands of mutations and different lineages have already emerged in the SARS-CoV-2 genome since the virus emerged in late 2019. As mutations continue to emerge, new variants are increasingly 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 occurred in the new UK strain involving the gene encoding the SARS-CoV-2 tip protein, which is associated with the entry of virus in cells and influences the immunity and effectiveness of the vaccine.
5. Will the vaccines still be effective?
It is currently unknown to what extent SARS-CoV-2 may evolve to escape infection-induced immunity or vaccination. There are ongoing studies to better understand it. Van Kerkhove of the WHO told the BBC that current information suggests the new variant has no impact on vaccine launches. Over time, as more mutations occur, vaccines may need to be altered. This happens with the seasonal flu, which changes every year, and the vaccine adjusts accordingly. Unlike the flu, coronaviruses have a test-reading mechanism that means they do not mutate as quickly as the flu virus. Covid-19 vaccines that have so far been shown to be effective in trials may be it was easily modified if necessary, BMJ medical journal reported on Dec. 16.