The new coronavirus strain has been discovered in Canada as public health leaders warn the US could have failed to detect the more infectious variant.
Two cases of the Sars-Cov-2 variant first sequenced in the UK were identified in Canada on Saturday after it was found in countries across Europe, in Japan and in Australia. The Canadian patients had not travelled to the UK, making it likely that the new strain is spreading within the community.
Dr Barbara Yaffe, Ontario’s associate chief medical officer of health, said the discovery “further reinforces the need for Ontarians to stay home as much as possible”, as the Canadian province began a shutdown on Saturday.
The new strain — which some scientists fear may be up to 70 per cent more transmissible — has not yet been found in the US, leading the Trump administration to require visitors from the UK to get tested from Monday.
But the US Centers for Disease Control and Prevention warned that the country did not do enough genetic sequencing of the virus to be sure it was not already circulating.
“Given the small fraction of US infections that have been sequenced, the variant could already be in the United States without having been detected,” the agency said on its website.
The US has only sequenced the virus that infected about 51,000 of the 17m people who have had positive Covid-19 test results, the CDC said. By contrast, the UK conducted far more extensive genomic surveillance, sequencing almost 10 per cent of all positive tests, according to the Covid-19 Genomics UK Consortium’s latest analysis, which used data from up until mid-November.
Angela Rasmussen, a virologist at Georgetown University, said the travel restrictions were “too little too late”.
“It’s likely this variant is already here and we just haven’t detected it yet,” she tweeted. “Why? The woeful state of genomic surveillance in the US. This is a major weakness we need to correct.”
The new variant of the virus appeared in Kent in the south-east of England in late September. By the week ending December 9, it accounted for 62 per cent of the infections in London.
Dr Anthony Fauci, the top infectious disease doctor in the US, said mutations were always “concerning” but he tried to soothe the American public by saying there was no evidence it appeared to lead to a more serious illness.
“The other issue is that, does it escape the protection that’s induced by the vaccines that we’re currently using? And, according to our British colleagues, that does not seem to be the case,” he told CNN’s State of the Union on Sunday.