Scientists are scrambling to understand a new Covid-19 variant that has been spreading rapidly in London and the South East of England.
The “VUI – 202012/01” strain is believed to be more transmissible – but there’s no evidence yet that it causes more serious illness.
Here’s what we know and what we don’t know, according to some of the country’s leading experts.
What’s different about the new strain?
The virus that causes Covid-19 has been mutating constantly since it was first identified in January this year.
This isn’t a surprise – all viruses change over time due to genetic mutations.
Many changes are random and do not make the virus more dangerous.
The VUI – 202012/01 strain is unusual because of the high number of mutations (22) and because a number of these changes affect the spike protein – the bit of the virus structure that binds to receptors in human cells and allows the disease to infect us.
Why are scientists worried?
Analysis of the new strain showed that it could have structural advantages over other variants that make it easier to infect people and spread more quickly through the population.
Professor Neil Ferguson from Imperial College London said the most recent figures suggest that the new strain is 50 to 70 per cent more transmissible, in the context of the control measures in place in England.
He added that there was a “hint” that the new variant may be more likely to infect children.
There is no evidence yet that the genetic changes make the symptoms of illness more severe.
Scientists will be performing laboratory experiments in the coming days to see how VUI – 202012/01 reacts to antibodies that have been shown to fight versions of the illness.
This should give an insight into whether the vaccines that have already been developed, as well as antibody-based treatments like convalescent plasma, will prove to be as effective against the new strain.
And analysts will be looking at hospitalization and death rates to see if there is any evidence that the coronavirus variant is more dangerous.
How did it start?
Researchers say one hypothesis is that an individual with a compromised immune system played host to the disease for a long period of time, allowing an unusually high number of mutations to take place.
But this has not been confirmed and no “patient zero” has been identified.
Professor Peter Horby from Oxford University, the chair of the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), said: “It’s just speculation, but there have been case reports in literature of this happening, not just with this virus but with viruses in the past.”
Is this really a “British strain”?
Scientists say the new strain does appear to have begun in Kent, although other European countries have reported low numbers of cases.
Professor Wendy Barclay from Imperial College London said the genetic fingerprint of the new Covid-19 variant was “unique to the UK” although South Africa has reported a similar strain that appears to have evolved independently.
Dr Susan Hopkins from Public Health England said: “This very much looks like a point source in England that then emerged and spread, so I think that it is very likely it emerged here.”
Will vaccines still work?
Professor Barclay said: “We’re not completely confident at the moment, and it’s very important that we carry out some analysis of that very quickly.”
Only one mutation affects the area where the virus spike protein binds to receptors in human cells, she added, whereas people who get vaccinated make antibodies which attack the protein in several different ways.
“It would be unlikely that this single mutation would throw off the ability of all the antibodies that are raised against the vaccine to see the virus.
“But there’s a possibility that the ability of the antibodies to see the virus is compromised to some extent, and that’s what we need to check out.”
New vaccine techniques like the use of RNA to prime the immune system means that scientists should be able to re-engineer vaccines to adjust to new strains more easily than in the past.
Was the government slow to act?
There has been a lot of comment today about scientists and ministers knowing the new strain was in circulation as early as September. In fact, this has been slightly misreported.
Scientific advisers say the alarm was not raised about the potential danger of increased transmissibility from VUI – 202012/01 until December 8.
An investigation was quickly launched which looked back at data from previous months and found that the new strain had been spotted as early as the middle of September.
But it was just one of many variants that are routinely monitored and was not considered a threat to public health at that time.
Rapid epidemiological analysis showed that the new strain could be linked to rapidly rising case numbers in London and the South East, at a time when infections were falling in other parts of the UK.
Prof Horby said preliminary data about the virus was first given to the NERVTAG advisory group on December 11.
A week later, on December 18, after analyzing more data, scientists issued a warning to the government about a “substantial increase in transmissibility” from the new strain.