It’s called XBB.1.5 and it could cause surprises in the coming weeks. Will this Omicron subvariant, which is experiencing “impressive growth” in the United States, play the spoilsport after the holiday?
Updated yesterday at 11:24pm.
COVID-19 has not yet spoken its last word. At the beginning of the new year, it is the XBB.1.5 sub-variant that is causing a stir.
According to the Centers for Disease Control and Prevention (CDC), XBB.1.5 was responsible for more than 40% of COVID-19 infections in the United States at the end of December.
This subvariant “arose from the recombination of two viruses, descendants of BA.2,” explains Gaston De Serres, medical epidemiologist at the National Institute of Public Health of Quebec (INSPQ).
The contagiousness of this virus has increased compared to its predecessors because it is “easy to attach”, he explains. “It probably takes a lower infectious dose to make someone sick,” says Dr. De Serres.
The growth of the virus is “impressive,” says infectious disease specialist and microbiologist Donald Vinh of McGill University Health Center, citing the example of the United States, where XBB.1.5 is on track to become the dominant variant.
A growth rate unknown in Canada
What about Quebec? Among all variants of the COVID-19 virus identified by the INSPQ, XBB.1.5 is in the Other category. We’ll have to wait until next week for more accurate data, explains Dr. Vinh.
Health Canada told La Presse that as of January 4, 2023, it was aware of “21 instances of XBB.1.5” in the country.
“Proportions and growth rates will not be known until enough data is available,” we were told.
So far there is no evidence that XBB.1.5 causes more serious diseases, says Gaston De Serres.
“At the moment there is no data to suggest that the virus is more virulent. Virulence is the ability to cause severe symptoms, hospitalizations, or death,” explains Dr. De Serres. But, he says, the more contagious a virus is, the more people will be affected.
Donald Vinh reminds that “the severity of the disease is also a function of the protection we have”.
“If we are sufficiently vaccinated with a booster shot, that protects us best,” says Dr. Vinh.
The Ministry of Health and Social Affairs also says so.
“According to the scientific data currently available, there is currently no evidence that the XBB subline is more virulent than the BA.5 subline. Bivalent vaccines also appear to offer better protection against these sublineages than monovalent vaccines,” writes spokeswoman Noémie Vanheuverzwijn.
A sub-variant to look at
Just before the holidays, the proliferation of respiratory viruses was being felt in schools across the province. One in ten students in Quebec was absent for the week of December 19.
What can we expect next week when everyone returns to class?
“For respiratory viruses in general, school is the driving force behind these epidemics of annual respiratory infections,” observes Gaston De Serres.
Nevertheless, one can assume that “it will be less intense” than before the Christmas holidays, says the epidemiologist, because influenza, like the respiratory syncytial virus (RSV), is in a “quite significant” decline.
The “uncertain part” remains XBB.1.5.
“What role will it play and how quickly will it develop? I’d be embarrassed to predict it exactly,” says Dr. De Serres.
For his part, infectiologist Donald Vinh believes we risk seeing a “small surge” in influenza and RSV in the community, but also in the XBB.1.5 subvariant.
“We will have an increase in cases. Will the number of hospital admissions increase as a result? it’s fear We’ll see the impact on the healthcare system in two or three weeks,” says Dr. Vinh.