It is too early to draw “strong conclusions” about whether the new variant found in Kent last autumn is associated with increased mortality rates, according to a member of Sage subgroup the Scientific Pandemic Influenza Group on Modelling (Spi-M).
Boris Johnson announced on Friday that the first major study of the mutation – which emerged in Kent last month – had found evidence that it is up to 30 per cent more lethal as well as being up to 70 per cent more infectious.
Dr Mike Tildesley, a professor of infectious disease modelling, told the BBC he “was actually quite surprised the news had been announced at a news conference”.
“It seems to have gone up a little bit from about 10 people per thousand to about 13 which is quite a small rise but it’s based on a relatively small amount of data,” Dr Tildesley added.
“I would be wanting to wait for a week or two more, monitoring a little bit more before we draw really strong conclusions about this. I just worry that where we report things pre-emptively where the data are not really particularly strong.”
Public Health England medical director Dr Yvonne Doyle also said, on Saturday morning, it was still not “absolutely clear” the new variant was more deadly than the original strain.
Dr Doyle said more work was needed to determine whether that was actually the case.
“There are several investigations going on at the moment. It is not absolutely clear that that will be the case. It is too early to say,” she told the BBC Radio 4 Today programme.
“There is some evidence, but it is very early evidence. It is small numbers of cases and it is far too early to say this will actually happen.”
However Professor Peter Horby, who chairs the Government’s New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), defended the Government’s decision to announce the news.
“I think a very important principle is transparency,” Prof Horby told BBC. “Scientists are looking at the possibility that there is increased severity… and after a week of looking at the data we came to the conclusion that it was a realistic possibility.
“If we were not telling people about this we would be accused of covering it up.”
But he added: “What we need to do is get that message out and put it in context. So instead of headlines saying ’30 per cent increase in risk’, we need to explain this in terms of the absolute risk we may be seeing and also explain the uncertainties.”
On a more positive note, Prof Horby said it was “encouraging” that B.1.1.7, the variant first found in Kent, did not appear to be more resistant to current treatments or vaccines.
“The encouraging news is that the UK variant is not affecting how the treatments work and it’s not affecting how the vaccines work, so we believe the vaccines and the treatment are just as good against this virus as they’ve always been.”