Omicron subvariant BA.2 more transmissible but not more virulent: Quebec report

The subvariant of the novel coronavirus that accounts for most COVID-19 infections in Quebec is more transmissible than the previous Omicron strain, but it is not more virulent, the province's public health institute said Tuesday.

About 90 per cent of new COVID-19 infections randomly screened in Quebec since mid-April involve the BA.2 subvariant, which replaced the original Omicron strain -- BA.1 -- responsible for a surge in infections last winter.

On Tuesday, the Institut national de sante publique du Quebec said, "The risks of hospitalization or any other serious illnesses related to BA.2 were comparable to those associated with BA.1."

The institute's report found that vaccines were 10 per cent to 40 per cent effective at preventing symptomatic infections in the six months after the second dose. A third dose increased the effectiveness against symptomatic infection to between 40 per cent and 74 per cent.

"Vaccine effectiveness for preventing hospitalizations or deaths linked to BA.2 remained elevated (77 per cent to 85 per cent) even seven months after the second dose," the institute said. A third dose or an infection following vaccination increased that to between 98 per cent and 100 per cent.

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Meanwhile, Quebec reported a 25-patient increase in COVID-19 hospitalizations on Tuesday and 27 more deaths attributed to the novel coronavirus. The Health Department said 2,195 people were in hospital with the disease, after 141 people were admitted in the previous 24 hours and 116 were discharged. It said 76 people were in intensive care, a decline of two over the same period.

Health officials reported 1,194 new cases detected through PCR testing, with 9.2 per cent of tests analyzed Monday coming back positive.

-- This report by The Canadian Press was first published May 3, 2022.