The Omicron BA.2 sub-variant is sweeping across many countries in Europe and Asia, where it is poised to once again overwhelm hospitals. This cousin of the original Omicron variant has made its debut in Quebec. It is currently believed to be responsible for half of new cases. Experts are proposing strategies to prevent this new variant from dragging our healthcare system into another critical situation.
It is known that the new BA.2 version of Omicron is 40% more transmissible than the original BA.1 version. Although we do not yet have clear data on its virulence, nothing confirms that it would be more dangerous than BA.1, which was less so than Delta.
But, “we saw that even if the first version of Omicron was less virulent than the previous variants, it still led to a collapse of our health system. So you can’t say that Omicron was benign,” Dr.r Don Vinh, microbiologist-infectiologist at the MUHC. “Thus, if the BA.2 variant is found to be equivalent to BA.1 in terms of pathogenicity, i.e. its ability to cause serious disease, this does not mean that it will have little impact on our healthcare system. We can already see that BA.2 threatens the health systems of several countries in Europe and Asia. »
According to computer modeling carried out by experts from the Canadian network CoVaRR-Net (Coronavirus Variants Rapid Response Network), the relaxation of sanitary measures combined with the greater transmissibility of the Omicron BA.2 subvariant could double the number of infections in the country compared to what it would have been if the restrictions were not lifted.
To deal with this sub-variant which is in the process of replacing the original Omicron variant, several European countries are offering a fourth dose of the vaccine to vulnerable and elderly people. In Quebec, immunocompromised people can receive it since mid-January, and people aged 80 and over will be entitled to it starting next week.
“It’s not just the immunocompromised and the elderly who are vulnerable, young people have been hospitalized and died from COVID-19. People need to receive three doses to be adequately vaccinated, two doses are not enough to be protected”, underlines the Dr Vinh.
The Dr Vinh believes that even people under the age of 80 will likely need a fourth dose more than four months after their third dose, given that “the vaccine we currently use has limited impact against newer variants.” The United Kingdom is considering it for next autumn in anticipation of a possible winter wave.
Third dose becomes more essential than ever as restrictions ease, warns Pr Nazeem Muhajarine, co-director of the Impacts on public health axis of the CoVaRR-Net.
More circumspect, the virology expert at UQAM Benoît Barbeau thinks that we must wait to see how we will manage to control this new BA.2 wave before considering extending the administration of a fourth dose to a larger population which, he recalls, has been heavily infected with the Omicron variant.
Measures with great effects
Experts agree, however, that we should maintain, and not suspend as the government plans, health measures to minimize the transmission of the virus, such as wearing a mask in interior spaces and more substantially improving ventilation. of these places.
“Wearing a mask indoors is a very small inconvenience for a huge gain in prevention. Ensuring good ventilation and going outside when possible are also ways to reduce transmission. And if you have symptoms, get tested and stay at home, ”recommends the Pr Muhajarin.
“Without going back to draconian measures like those we experienced this winter, the government should perhaps consider maintaining the wearing of masks in indoor places, if only for the time to get through this new wave, even until the summer season,” says Mr. Barbeau.
“It would have been preferable to lift the sanitary measures more gradually”, affirms the DD Cheryl Camillo, CoVaRR-Net member. Because there is “the danger that many Canadians believe that, because the restrictions have been lifted, there is no longer a risk. These people could then choose not to use all the prevention tools at our disposal”, worry the researchers of this network.