BA.4 and BA.5 variants are fueling the growing number of cases in the US, Europe and elsewhere around the world.  In Canada, the two variants accounted for 3.9 percent and 6.5 percent of COVID-19 cases, respectively, according to samples collected in the week of May 29th.  Cases of BA.2.12.1, another growing subvariable, also account for 40.5 percent of cases.
In a press release on Friday, Canada’s Medical Director of Health, Dr. Theresa Tam, noted the development of these subtypes, saying they “have shown a growth advantage in additional immune leakage” over previous variants, citing a reduction. vaccine immunity and virus evolution.
“We do not expect our progress to be linear, so maintaining readiness for a potential resurgence that could have a serious impact is our best asset,” Tam told reporters.
Toronto-based emergency physician Dr.  Kashif Pirzada says the rise of these variants shows how fast 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 have waves every two to three months,” he told the CTV News Channel on Saturday.  “The crazy thing is that immunity from a previous infection, even if you received the Omicron on the wave in January or last month – may not protect you from this variant because it is so different that your immunity will not be strong enough to ‘her. “
In Portugal, where variant BA.5 accounted for 87 percent of cases on May 30, hospital admissions 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 percent and 13.3 percent of COVID-19 cases in the United States, respectively.
“If you look at countries like Portugal, which got the BA variant.5 … this is one of the highest vaccination rates in the world and you see a sharp increase in hospitalizations there. So that could be a warning to us.” , “said Pirzada.” Hopefully the summer weather here and the schools they are dropping out of now will prevent us from doing so badly, but it means we have to be careful. “
Canada is currently seeing low rates of cases and hospitalizations, and Tam said the Canadian Public Health Service is “cautiously optimistic about the current course”.
“If you compare where we are now, compared to where we were, you know, a month and two months ago, we were doing much better,” said infectious disease specialist Dr.  Isaac Bogoch on CTV News on Friday.
However, Bogoch believes there could be a “summer collision in cases, depending on how it happens”, citing Ontario wastewater data showing a recent increase in SARS-CoV-2 concentrations.
“It shows a slight bang on the signal and I do not think it is just a flicker,” he said.  “I think this is the real deal because if you look at different parts of Ontario and this is not geographically unique in one area. You see this signal in many geographical areas.”
With files from CTV National News Toronto correspondent John Vennavally-Rao.