New variants, resistant to certain treatments and capable of outwitting the immune system, are rapidly gaining ground in Quebec. Researchers and doctors are concerned about the rapid rise of the BQ.1.1 lineage, which is very present in Europe, which could soon limit the treatment options for patients who are infected with it.
Data from the Public Health Laboratory of Quebec (LSPQ) show that the descendants of Omicron from the BQ.1.1 line are gaining ground in Quebec, indicates Inès Levade, specialist in clinical biology at the LSPQ. This line, which represented only 0.4% of the variants in circulation in September, accounted four weeks later (from October 2 to 8) for 4.4% of the sequenced variants. The small decline observed in the new data on variants unveiled on Wednesday (3.7% on October 15) by the National Institute of Public Health of Quebec (INSPQ) would be only a hiatus frequently observed in emerging variants, according to the researcher.
“With the data we have, [on peut dire] that BQ.1 and BQ.1.1 are on the increase, and we expect to see an increase similar to what is observed in Europe and the United States”, explains Inès Levade.
The BQ.1.1 line, already at the origin of 16% of the cases detected in the United States and France, and 50% in Île-de-France, is on the way to replacing the famous BA.4 and BA.5 still dominant on the Old Continent. To the point that the scientific council on COVID (COVARS) in France felt the need to recommend on October 20 a booster vaccination and the wearing of a mask. According to predictions from the European Center for Disease Control and Prevention (ECDC), this variant could account for half of infections in Europe by the end of 2022 and for 80% in 2023.
“We also saw here that it was doubling every week. And in Canada, it is in Quebec that there are the most,” adds Ms.me Leavening.
However, data from a Chinese research team, not yet peer-reviewed, demonstrate that immunity conferred by three vaccines (Coronavac) and prior infection barely manages to neutralize this new subvariant. The same is true for its cousin, the XBB variant present in Asia, detected for the first time in Quebec in early October.
The B.4.6 variant, responsible for approximately one in six cases in Quebec (16% in mid-October), is also resistant to monoclonal antibodies and capable of partially escaping the immunity conferred by first-generation vaccines or by a previous infection.
These variants have a mutation giving them resistance to most monoclonal antibodies available in Canada, including Evusheld given to immunocompromised people to help them fight the disease. The rise of BQ.1.1 worries doctors, whose therapeutic arsenal is once again amputated by another effective weapon.
“It influences the care we can give. If BQ.1.1 continues to grow, that means that for one in five patients infected with these variants, these treatments may no longer work. We’re running out of options,” says the Dr Donald Vinh, immunologist and infectious disease specialist at the McGill University Health Center (MUHC).
Added to these newcomers is the XBB variant that arrived on Quebec soil. Responsible for the current waves in particular in India and Singapore, XBB would be equipped with an increased capacity to circumvent the defenses of the immune system, conferred by a vaccine or an infection with the preceding variants.
“It’s worrying to think that, for vulnerable patients, we have fewer and fewer options,” says Ms.me Leavening. There remains Remdesivir, which is an antiviral, and Paxlovid, both still effective. There is an absolute need to develop new treatments. »
The LSPQ also frequently sequences samples from patients hospitalized with COVID-19 to help doctors know which treatments may still be useful.
Andres Finzi, immunologist and researcher at the CHUM Research Center, is testing in vitro the ability of the immune system of people exposed to the original Wuhan strain virus to recognize and neutralize these new subvariants. He notices that it has been steadily withering since Omicron’s arrival.
The B.4.6 variant, he says, manages to trick the immune system in those who received a vaccine and had an infection just four months ago. It will soon test the impact of BQ.1.1. on the immune system. “What happens in New York and in Europe is likely to happen here. Everyone should get a fresh dose of the bivalent vaccines,” he says.
Focus on mutations
About 700 samples are sequenced each week by the public health laboratory to monitor the variants present, with a delay of 7 to 10 days compared to daily reality. The data published by the INSPQ, for their part, are about two weeks behind the current state of the pandemic. But, according to Inès Levade, it is not so much new variants as certain specific mutations that researchers keep an eye on.
No studies to date indicate that BQ.1.1 causes more severe symptoms, says Ms.me Leavening. On the other hand, people who develop a serious infection will have fewer tools to fight it. It’s hard to say if BQ.1.1 will dominate in Quebec this winter as expected in Europe. “Often, says the researcher, the first to arrive with these mutations takes over and sets the tone for the coming months. »
Since Omicron, several variants have developed resistance to most monoclonal antibodies available. The experimental cocktail tested on President Donald Trump in 2021 would be of no use today against the descendants of Omicron. “This is why the bivalent vaccine is essential. Our permissiveness allowed the virus to circulate and these mutations to emerge. The selection is made in favor of variants that are constantly more resistant and more transmissible”, notes Dr.r Vinh.
Even if he is in favor of it, the latter considers it unthinkable that Quebec should return to collective health measures. “We have crossed the Rubicon, there is now a psychological barrier. The mask was discontinued for fairly benign reasons, such as discomfort. Now it’s every man for himself, he laments. I fear that the winter wave, combined with the other respiratory viruses, will create a hurricane. It will always be the same people who will suffer: the young and the old.