New data obtained by The Ferret shows how a more infectious ‘Kent’ variant of Covid-19 spread rapidly throughout Scotland to become the dominant strain in just a matter of weeks.
Experts have warned it highlights the potential for a rapid spread of other more infectious strains of Covid-19.
They say public health bodies must continue to keep testing for new virus variants and keep case numbers low – even after the Scottish population is widely vaccinated.
The data, obtained through a freedom of information request from Public Health Scotland, shows the more infectious ‘Kent variant’ of Covid-19 was first detected in Scotland in early November 2020, after being spotted in the south of England a month earlier.
The records show that even in the first week it was detected in Scotland, there were already 23 cases of ‘Kent variant’ in the country.
Those included eight cases found in the Glasgow and Clyde NHS board area, as well as smaller clusters in Fife, Lanarkshire, Lothian and Tayside.
Cumulative number of cases identified as ‘Kent variant’ Covid-19
Within six weeks there were cases of the ‘Kent variant’ in nearly every health board area of Scotland, with around 400 detected by the start of December.
By January, as Covid-19 case numbers rose rapidly towards a post-Christmas peak, test results show that the ‘Kent variant’ – sometimes known by it’s scientific moniker ‘B.1.1.7’ – had become the dominant strain of the virus in Scotland.
By 23 February more than 43,000 cases had been identified in Scotland.
The most recent data released by Public Health Scotland shows that the more virulent Kent strain accounts for more than 90 per cent of all Covid-19 infections tested.
More dangerous and more deadly
The B.1.1.7 strain is regarded as both more infectious and more deadly than previous strains, although a January 21 report from the NERVTAG group of scientists advising the government noted that “the absolute risk of death per infection remains low.”
Nevertheless, it has become the dominant variant throughout the UK and has been detected on every continent in the world, apart from Antarctica.
Commenting on the data for Scotland, Professor David Robertson, Head of CVR Bioinformatics MRC at the University of Glasgow Centre for Virus Research (CVR), said: “B.1.1.7 was already fairly spread in the UK by the time its increased transmission properties were understood.
“This demonstrates how quickly the virus can spread, exactly as we saw with the first wave last year, and just as with last year the need for stronger lockdown measures.”
He said that had the authorities followed scientific advice from the UK Scientific Advisory Group for Emergencies (SAGE) and introduced tighter lockdown restrictions earlier in the autumn, the spread of the Kent variant may have been slowed.
“SAGE had called for lockdowns to be imposed sooner which would have minimised B.1.1.7’s wider spread in the UK,” he said.
The spread of the B.1.1.7 variant is reduced by the vaccines that are being distributed in Scotland. More than a third of all adults in the country have received a first shot of a covid-19 vaccine.
Professor Rowland Kao, Chair of Veterinary Epidemiology and Data Science at the University of Edinburgh, said he was “cautiously optimistic” that the vaccine would keep the more virulent Covid-19 strain under control as the country prepares to start lifting lockdown restrictions once again.
“Vaccination is really starting to show signs of having an impact and impacts transmission, so we have reason to be cautiously optimistic,” he added.
However, he said cases of the virus had come down under “extreme” lockdown rules restricting mixing.
“Under current conditions, we definitely know the variant is controllable by restrictions,” he said. “It is more of an open question as to whether or not that would change.
“How much more transmissible will it be in the absence of extreme lockdown? We shall find out.”
What about other strains of Covid-19?
Viruses mutate naturally over time as they are transmitted. Tens of thousands of different strains of Covid-19 have already been documented by scientists working around the world.
Many Covid-19 mutations are inconsequential, although they can still be used to track how the virus spreads.
Some new variants become known as “variants of concern” if scientists suspect that they may be more infectious than their predecessors, or able to evade existing vaccines more effectively.
Experts may be optimistic about the ability of existing vaccines to quash the spread of the Kent variant, but worries remain over other new ‘variants of concern’ of the coronavirus, both known and unknown.
Among the known variants of concern, both Professor Robertson and Professor Koi highlighted the potential for a “Brazil” variant of Covid-19 to reduce the effectiveness of the vaccines currently in use.
It was reported that three oil workers returning to Aberdeen from Brazil had already brought the Brazil variant into Scotland.
Officials are reportedly still trying to trace all the contacts of the people who shared a plane with the three workers from Heathrow to Aberdeen.
Professor Robertson said it was “concerning” that some of “the newer variants that are circulating… can have some impact on vaccine success.
“The vaccines will still provide high levels of protection and prevent most cases of high disease severity but it will be important to monitor these and other new variants,” he added.
“The vaccine can be updated to account for the new variants so we are in a strong position to respond to the virus.”
But he believes the potential for new strains to emerge makes testing capacity all the more important.
Professor Koi is also concerned that other variants may be harder to detect, and claims that in some respects the UK “got lucky” when it comes to monitoring the Kent variant.
The Kent variant is missing a gene that is routinely tested for as part of the PCR test process commonly used in the UK, allowing it to be traced more easily than some other variants.
“Other variants are not so conveniently picked up by the PCR tests and so we have to find them via sequencing,” Koi explained. “Sequencing capacity, last I looked, could handle about 10 per cent or less of all positive tests.”
The UK as a whole has the capacity to sequence around 25,000 positive tests per week.
As the overall number of infections comes down, the proportion of positive tests that can be sequenced for new variants may increase, but Koi added, “this is yet another reason we want to get the numbers of cases down” – as it is, “much harder to quash any variants of concern if we can’t automatically identify them.”
A Scottish Government spokesperson said: “As the First Minister set out in the Strategic Framework Update, we have been acutely aware of the impact of the new, much more transmissible and potentially more harmful variant of the virus (known as B117 or the ‘UK’ or ‘Kent’ variant) was detected and has now come to be the predominant strain of the virus in Scotland.
“When incidence rose in December, partly as a result of the increased transmissibility of the new strain we acted firmly and fast to introduce new safety measures, in particular on December 26th and January 4th. These measures have worked to reduce spread of the new variant.
“We have been clear that we must be careful not to ease restrictions too quickly. If we do move too quickly, transmission could quickly rise and that would lead again to significant mortality and morbidity and risk overwhelming our NHS. We are also clear though on the harms that continuing restrictions have on the economy and mental health, which is why we evaluate measures using our Four Harms methodology.
“Our aim continues to be to suppress the virus to the lowest possible level and keep it there, while we strive to return to a more normal life for as many people as possible, and we will continue to be cautious and gradual and informed by the latest evidence and data, including analysis of the impacts of both new variants and of vaccinations.
“Our continued focus on safe international travel, including the use of managed isolation, is a crucial tool in our fight against new variants, particularly as our incidence falls ”