Four cases of BA.2 Omicron subvariant found in Manitoba

There have been four cases of the Omicron sub-variant BA.2 found in Manitoba.

A provincial spokesperson tells CTV News on Friday the first case was discovered on February 8, and the others were detected this week.

“The province has always had a robust system to detect variants utilizing samples from across the province to ensure that the introduction of a new variant is detected and communicated to public health,” reads the provincial statement.

At Thursday’s health system update, Dr. Brent Roussin, Manitoba’s Chief Provincial Public Health Officer, said the province had not seen significant levels of transmission at this point of BA.2.

“There’s a suggestion this is more transmissible than the original strain of Omicron, but (we are) not seeing a lot of evidence regarding that it’s more severe,” he said. “So, we’ll continue to follow the numbers, we are still sequencing a significant proportion of our cases. We just haven’t seen a lot of BA.2 at this point.”

The province also told CTV News Friday that Cadham Lab routinely sequences about 10 per cent of all PCR positives from across Manitoba or at the request of public health.

“Introduction or establishment of any new strain would be detected using this sampling method,” the statement went on to say. “To date, Omicron BA.1 is by far the most dominant and established strain, brief introductions of Delta or BA.2 have been noted recently but do not seem to be establishing themselves.”

University of Manitoba immunology research associate Julie Lajoie told CTV News that BA.2's impact is hard to predict.

"If everything was staying in place right now, all the restrictions, I would not be worried too much about BA.2," she said. "I think we could contain it, but right now everything is opening so much and we are missing a lot of data."

Part of that missing data she said is the limited access PCR testing in Manitoba.

"So if we have already four cases within those limited people who have access to PCR, that means we have a lot more cases in the community."

She said BA.2 is likely in the community but at which level it is really hard to know.

She pointed to Saskatchewan where she said BA.2 cases, where the most recent wastewater data from the University of Regina was available, shows BA.2 makes up for around 18 per cent of viral load. Lajoie said Manitoba is likely somewhere in that range, maybe a bit lower.

Lajoie described BA.2 as the sibling of BA.1. She said the Omicron variant is its own branch on the COVID-19 tree which is made up of BA.1, BA.2, and BA.3.

"They have genetic similarities but they are also different. BA.2 has a few more mutations in the spike protein."

She said what is known about BA.2 currently is that it's more transmissible than BA.1, but the severity of the disease is hard to measure.

She predicts BA.2 will probably take over BA.1 but isn't sure how long it will take because BA.2 is arriving at a time of change.

"We are, as a country and as a province in Manitoba, are opening and opening things quite fast," she said.

It is also a time when Manitoba is on the other side of the big Omicron BA.1 wave, but Lajoie said it's not clear how much immunity will come from a large number of infections.

Other factors at play she said are the plateau of COVID-19 vaccine doses -both the third doses and shots given to the 5-11-year-old age group, and the fact that children under five are still unprotected.

"There are a lot of things going on at the same time that the new variant is arriving and it's really hard to know what's going to be the impact."

She would like to see access to PCR testing expanded or a rapid test reporting system to be established, as well as keep mandatory indoor masking and for public health to push the importance of the third dose.

She said the surveillance Manitoba is left with is wastewater and hospitalizations, two factors that are delayed by a week or two.