Omicron | BA.2, the sub-variant that raises questions

A new variant has appeared on the planet. It is actually a sub-variant of Omicron, called BA.2. It began to spread to Denmark, Great Britain, India and several other countries. Will this sub-variant dethrone BA.1, Omicron’s original strain? Is it more virulent? More contagious? Does he threaten Quebec? Here’s what we know.

Suzanne Colpron
The Press

The BA.2 is a derivative of Omicron

It’s a closely watched sub-variant of Omicron. As we know, the virus responsible for COVID-19 is a coronavirus that constantly undergoes mutations over its replications, which gave us the Delta variant, and more recently Omicron. It continues to change. To the initial strain, the one that hit Quebec, the BA.1, are now added the BA.2 and the BA.3, which are very much in the minority. BA.2, which differs from Omicron by just over 20 mutations, is already dominant in Denmark and India, where contamination has started to rise again. Since its appearance, it was first spotted in India, at the end of December 2021, and quickly spread to many countries, including Israel, the United Kingdom, Belgium and France.

It is called “stealth”.

It is also called “stealthy” because it is particularly difficult to detect. In the case of the original Omicron variant, it was thanks to a missing element in its genetic material, what scientists call a deletion, that it was easily identified. By deduction, with screening, because this element was absent, we knew it was Omicron. “In BA.2, this deletion does not exist. So our screening test would not work. It is absolutely necessary to do genetic sequencing of the virus to distinguish BA.1 from BA.2,” explains Nathalie Grandvaux, researcher at the research laboratory on the host response to viral infections at the Center hospitalier de l’Université de Montréal ( CHUM).

According to Alain Lamarre, professor-researcher specializing in immunology and virology at the National Institute for Scientific Research, it is for this reason that it took weeks to spot it. “He’s been in Britain since December 6,” he said. But it wasn’t that long since we realized he was there. That’s why it was called “stealth” because it went under the radar for several weeks. »

We do not know if he is in Quebec

Is it in Quebec? We ignore it. “We know that the representation of the BA.2 is very low elsewhere in Canada. But we have no information on Quebec, ”says Nathalie Grandvaux. “For several weeks, there has been no footage from Quebec entered into the database. »

It doesn’t seem more dangerous

While it may be even more transmissible than the original variant, it does not appear to be more dangerous. “We think it has the same severity as BA.1,” says Benoît Mâsse, professor at the School of Public Health at the University of Montreal. But it’s something to watch, that’s for sure. What we learned with variants is that they tend to take us by surprise. »

Nathalie Grandvaux adds that the current data suggests that the original Omicron variant and the BA.2 are not so different. “With the data we have, in particular by analyzing what is happening in Denmark and England, in places where there are already a few or a lot of them, we do not clearly see differences in severity between the two, specifies she. For the moment, the experts think that there is not really to worry, at least for the dangerousness. On the other hand, in terms of vaccine escape, we need to have studies to know where it is. So that remains to be determined. »

Professor-researcher Alain Lamarre is of the same opinion: “There is no need to worry, he says. There are no indications that it is more dangerous. But we will have to follow this closely. If it were more transmissible, it could slow down the ideas of deconfinement… ”