Cases of COVID-19 infection and hospitalizations related to the virus have been on the rise since the beginning of July in Quebec. A scenario that has been repeated for two years and which suggests that this summer increase in cases will occur again in the coming years, according to a respiratory virus specialist.
“It’s hard to understand why we have an increase [à cette période de l’année] while we still live a lot outside, we haven’t yet returned to school, etc.,” says Nathalie Grandvaux, professor in the Department of Biochemistry and Molecular Medicine at the Université de Montréal (UdeM). This year, the increase in summer cases is somewhat early, unlike in previous years when early August was the norm, notes the specialist.
During the week of April 7, the Institut national de santé publique du Québec (INSPQ) recorded 290 positive cases of COVID-19. Three months later, during the week of July 14, the INSPQ counted 1,855. These data underestimate the reality, because they only include PCR test results and rapid test reports.
Respiratory virus outbreaks, such as COVID-19, generally occur during the winter period. “They are seasonal and often linked to the temperature, and to the fact that we are indoors a lot, and outside less, at least for countries like Canada,” explains Professor Grandvaux, giving the example of the flu, which generally returns in winter.
This does not mean that Quebecers are spared from COVID-19 in winter. In 2023, the increase in infections that began at the end of July continued to peak in the week of December 10, 2023, with 6,261 positive tests recorded by the INSPQ, before falling again until March 2024 when cases of infection became low again.
One of the factors that could explain the summer increase would be vaccination, which would lose its effectiveness.
“The most vulnerable people usually get vaccinated in the fall, so by the time we get to August, the effectiveness of the vaccination is less there. So that could be one of the factors in the increase in cases in August, [qui provoque] “more hospitalizations and also more deaths,” says Nathalie Grandvaux. “But there again, we don’t have any data,” she adds.
Is it the fault of new variants?
By email, the INSPQ indicates that “a summer increase is a phenomenon that has already been observed when new variants circulate. For example, the KP.3 and KP.2 sublineages appeared a few weeks ago and are now predominant. SARS-CoV-2 [virus de la COVID-19] does not currently exhibit a seasonal pattern comparable to other viruses and it is impossible to predict when or if such seasonality might be observed.”
Nathalie Grandvaux believes that it is not necessarily the variants that are responsible for the increase, recalling that they were very present in Quebec in April, when cases were not increasing. In addition, the variants “do not change the symptoms or the severity. It is more a question of vulnerable people who are infected, or not, [chez lesquelles] “We see hospitalizations or deaths,” she explains.
Good news to counter the KP.2 and KP.3 variants, “the vaccines that should be approved for vaccination for the fall will cover these variants,” underlines Mme Grandvaux.
Precautions remain necessary
The virology expert also insists that the main solution to avoid getting sick with COVID-19 is to be “up to date with your vaccinations.” “That’s the key word to remember,” she says.
Getting tested as soon as you have symptoms is also a good reflex to have. “In summer, it’s very unlikely that it’s the flu or that it’s RSV [Virus respiratoire syncytial] “, she says. Even if “it could be a classic cold, it’s always good to get tested to find out if you’ve had COVID-19 in relation to the potential risks of long-term effects,” says Nathalie Grandvaux.
The Quebec government website states that “the majority” of screening tests expire 24 months after the manufacturing date, which is indicated on the box, and that they “can be thrown in the trash” if their shelf life has passed. An expired test can “give a false negative,” explains Nathalie Grandvaux.
Whether the test is positive or not, “when you have symptoms, whether they are those of COVID-19 or other respiratory symptoms, you should take measures to avoid spreading the infection,” recalls Mr.me Grandvaux.