More than five per cent of COVID-19 cases on Jan. 20 were from variants of concern: officials

More than five per cent of positive COVID-19 cases collected last month in a major Ontario study tested positive for highly infectious coronavirus variants of concern, according to a new report.

Of the 1,880 positive samples from January 20 that were analyzed, 103, or 5.5 per cent were confirmed or highly likely to be either the UK B.1.1.7 or South African B.1.353 variants of concern.

Of those, 89 were from the Simcoe-Muskoka public health unit, with 85 of those directly linked to the Roberta Place long-term care home outbreak where 66 of 129 residents of the home have now died.

Other locations that generated variant cases on Jan. 20 were Peel (six cases), York Region (one case), Toronto (five cases), Waterloo (one case), and Durham (one case).

Of the 103 cases, 16 or 1.2 per cent were in the community and not associated with outbreaks like the one at Roberta Place.

Chief Medical Officer of Health Dr. David Williams said the overall result is small, but Ontarians should not get complacent as the variants are circulating in the community.

“It’s not an ‘oh well,’ we knew that it was circulating in the community around Christmas,” he said.

Public Health Ontario (PHO) and other allied labs have run most positive COVID-19 cases from Jan. 20 through enhanced analysis including full genomic sequencing as part of a “point prevalence” study.

About 3,003 positive samples were available for screening in the province from Jan. 20, but PHO could only obtain 1,880 of them.

As of yesterday, there were 153 confirmed cases of the variants in the province, along with dozens of additional highly probable variant cases tied to outbreaks at long-term care homes in Simcoe County.

The B.1.1.7 variant, first discovered in England, is approximately 50 per cent more transmissible than older “wild” variants of coronavirus present in Ontario.

Scientists have said the B.1.353 variant, first discovered in South Africa, is also more infectious than older variants and may also circumvent some of the immunity given by some COVID-19 vaccines.

The head of Ontario's COVID-19 Science Table has said the B.1.1.7 variant will become the dominant strain detected among positive cases by March.

PHO Chief Microbiologist Dr. Vanessa Allen said that they have observed the B.1.1.7 variant to have a doubling time of “every one to two weeks,” but she said more surveillance will need to be conducted to track its spread going forward.

As of now, all positive samples from Pearson Airport are immediately screened for the presence of the variant.

In the coming days, PHO will be able to check any positive specimen for the variant.

If the variants become dominant, existing public health measures will have to be prolonged or even enhanced in order to get spread under control, assuming mass immunity through vaccination is still months away.

That revelation has prompted the provincial and federal governments to introduce a series of new restrictions making air travel abroad more difficult.

Public Health Ontario said only three of the 103 variant cases detected from the Jan. 20 study were in people who had travelled abroad recently.

Variant cases are detected through a more detailed analysis of the results of standard PCR COVID-19 tests, coupled with more intensive and lengthy full genomic sequencing of the virus’ genetic profile.