After a difficult year in 2022, Quebec has observed a marked drop in deaths linked to COVID-19 in recent weeks. Hybrid immunity conferred by vaccines and infections with the virus could be to blame, experts believe.
Quebec is currently deploring two or three deaths a day due to COVID-19. This is significantly less than in 2022, when an average of 16 deaths were recorded per day.
“There are several factors that can explain this decrease in deaths, but what is most likely is hybrid immunity,” says Nathalie Grandvaux, researcher at the Laboratory for Research on Host Response to Viral Infections. of the University of Montreal Hospital Center.
This hybrid immunity is induced by vaccination and infection with the virus. Currently, three-quarters of Quebecers aged 60 and under have contracted COVID-19, with the majority of infections occurring in the past year.
In addition, most Quebecers are vaccinated. Indeed, 88% of people received at least one dose of vaccine and 30%, four. “Immunity in the current population in Quebec to protect against severe forms is very good”, summarizes Mme Grandvaux.
PHOTO WOLFGANG RATTAY, REUTERS ARCHIVES
The antiviral drug Paxlovid has been available in Quebec for almost a year.
The drug Paxlovid, available in Quebec since March 2022, could also have avoided certain deaths, estimates virologist Benoit Barbeau, professor in the department of biological sciences at the University of Quebec in Montreal.
“We now have more access to this antiviral and we have a better understanding of how to use it,” he says. Administration of Paxlovid, from Pfizer, reduces the risk of hospitalization and death in people at risk of complications.
COVID-19 remains present
One thing is certain, the drop in deaths does not seem to be attributable to the disappearance of COVID-19. The coronavirus continues to circulate a lot in Quebec, as shown by the data on wastewater from the main cities of the province.
COVID-19 also continues to put some pressure on the hospital network. There are currently 427 people hospitalized with COVID-19.
However, few of these patients represent serious cases. There are only 22 patients in intensive care due to COVID-19. Eleven other patients have COVID-19 in intensive care, but they were admitted for another cause.
“At the moment, we are a little in the calm after the storm, and we hope that it will last”, says Mme Grandvaux.
A sub-variant that takes its place
This drop in deaths coincides with the arrival of the XBB.1.5 sub-variant, which is rapidly taking its place in Quebec. At the beginning of February, the newcomer represented 28% of the cases detected. Its predecessor, BQ.1.1, is regressing, but still accounts for half of new cases.
However, the current data do not allow us to say whether this new subvariant causes more or less serious infections than the variants which circulated previously, indicates Mme Grandvaux.
“We can never predict what will follow, but I do not believe that this sub-variant will necessarily explode the cases”, estimates however Mr. Barbeau, in view of the current data.
“Even though the XBB.1.5 subvariant takes up more space, the number of hospitalizations decreases. In addition, we are heading in the coming weeks for milder temperatures, ”he said. Remember that a decrease in the transmission of respiratory viruses is often noticed when people spend more time outdoors.