As summer approaches and COVID-19 health measures continue to loosen, experts say the rise in Omicron subvariants could lead to a further increase in cases in Canada.
Subvariants BA.4 and BA.5 have been feeding a growing number of cases in the US, Europe and around the world. In Canada, the two variants accounted for 3.9 per cent and 6.5 per cent of COVID-19 cases, respectively, according to samples collected in the week of May 29. The cases of BA.2.12.1, another growing subvariant, also account for 40.5 percent. of cases.
Speaking at a media conference on Friday, Canada’s medical director of health, Dr. Theresa Tam, noted the growth of these subvariants, saying that “they have shown a growth advantage in the additional immune breakdown” over the variants. citing the decline in vaccine immunity and viral evolution.
“We do not expect our progress to be linear, so maintaining preparedness for a potential resurgence that could have a serious impact is our best advantage,” Tam told reporters.
Toronto emergency physician Dr. Kashif Pirzada says the increase in these subvariants shows how quickly the virus can mutate.
“It is evolving to beat our immunity and our vaccine and it looks like we will be in a world where we will have waves every two or three months,” he told CTV news channel on Saturday. “The craziest thing is that the immunity of a previous infection, even if you had Omicron in the January wave or during the last month, may not protect you from this variant because it’s different enough for your immunity not strong enough for that. “
In Portugal, where the BA.5 variant accounted for 87% of cases on 30 May, hospitalizations increased as a result. Last week, the Centers for Disease Control and Prevention announced that BA.4 and BA.5 now account for 8.3% and 13.3% of COVID-19 cases in the U.S., respectively.
“If we look at countries like Portugal, which received the BA.5 variant in the last two weeks, this is one of the highest vaccination rates in the world and there is an increase in hospitalizations there. that could be a warning to us, “Pirzada said. “Hopefully, the summer weather here and the schools being let out now will keep us from going so bad, but it means we have to be careful.”
Canada is currently seeing low rates of cases and hospitalizations, and Tam said the Public Health Agency of Canada is “prudently optimistic about the current trajectory.”
“If you compare where we are now, compared to where we were, you know, a month and two months ago, we’re doing much better,” infectious disease specialist Dr. Isaac Bogoch told CTV News on Friday.
However, Bogoch believes there may be “a summer blow in the cases, depending on how it develops,” citing wastewater data in Ontario that show a recent rise in SARS-CoV-2 concentrations. .
“It’s showing a slight rise in the signal, and I don’t think it’s just a blink,” he said. “I think it’s the real deal because if you look at the various areas of Ontario and that’s not geographically unique to an area. You’re seeing that sign in a variety of geographic regions.”
With files from CTV National News Toronto correspondent John Vennavally-Rao.
Wastewater data in Ontario show a recent increase in SARS-CoV-2 concentrations since early June. (Ontario Science Board)