A new sub-variant of Omicron is expected to become the dominant strain of COVID-19 in Ontario, health officials say.
According to the latest Public Health Ontario (PHO) epidemiological summary, sub-option BA.5 has “the fastest comparative growth rate of any line in Ontario”.
BA.5’s share of the positive case rose from 3.1% to 6.7% between the last week of May and the first week of June, officials said. The weekly growth rate is also 3.22 times higher than sub-option BA.2 in the last 12 weeks.
“Based on these European data and other data, as well as the fact that it appears to be more portable than option BA.2,” Dr Samir Patel, head of microbiology and laboratory science at PHO, told CTV News Toronto in Monday.
By the end of the month, Patel estimates that just over 50 percent of all COVID-19 cases in the province will be sub-option BA.5.
“This is in line with what we see internationally,” he added.
Omicron’s BA.5 sub-option stimulates an increase in cases in the United States as well as in many European countries. Last week, Chief Medical Officer Dr. Teresa Tam noted that BA.5 accounted for about 6.5% of COVID-19 cases in Canada.
Patel says health officials do not have enough information to say whether sub-option BA.5 is heavier than the others, but they are “keeping an eye”.
“It’s more portable, so we see a BA.5 infection in people who have received their full dose of vaccination, but we also don’t see a serious illness,” Patel said. “We need more data to be able to say emphatically that, yes, you know, people who are vaccinated can become infected, but the hospitalization rate or severity will be low.
Patel added that officials still recommend getting vaccinated against the new coronavirus, as this is likely to provide some protection against hospitalization, regardless of the sub-variant. This was reflected in new data provided by researchers at Beth Israel Deaconess Medical Center, who found that the new subvariants were more likely to avoid antibodies.
“These data show that subvariants BA.2.12.1, BA.4 and BA.5 essentially avoid neutralizing antibodies induced by both vaccination and infection,” the researchers wrote in the New England Journal of Medicine.
According to PHO data, as of June 17, just over 18% of patients hospitalized with at least two doses of COVID-19 vaccine were associated with subvariant BA.5. Patel claims that these statistics are not worrying, because the more a variant is spread, the more likely it is that it will naturally infect more people, regardless of the vaccinated status.
“We all need to get vaccinated,” he said. “If you qualify for the third booster, you must be vaccinated … (if you qualify for the fourth booster, you must also be vaccinated.”
It is not yet clear how the emergence of a new dominant strain will affect the total number of COVID-19 cases in Ontario or the provincial health system, but according to the data provided by the Scientific Advisory Table, it appears that the concentration of the new coronavirus in waste water begins to rise slowly.
Most regions, with the exception of the public health units in the south-west, are seeing an increase in the concentration of COVID-19 in wastewater signals.
Just one month ago, public health officials noted an increase in BA.2.20 sub-options in Ontario.
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