As is customary every fall since 2020, Canada is again witnessing a surge in COVID-19 infections and hospitalizations as summer gradually fades into September. Dr. Theresa Tam, Canada’s Chief Public Health Officer, during a televised technical briefing on Tuesday, attributed a portion of this upswing in COVID-19 transmissibility to new Omicron subvariants.
“The Omicron variant continues to transform,” Tam dissected, “with subvariants like EG.5 prolonging their circulation both here in Canada and around the globe.” On that very Tuesday, Health Canada greenlit a novel COVID-19 vaccine formulation from Moderna that targets the XBB.1.5 Omicron subvariant. First identified in the United States in October 2022, this strain swiftly superseded other circulating variants.
The strain made its first appearance in Canada come November 2022, subsequently giving birth to EG.5. EG.5 alongside another novel subvariant, BA.2.86, have recently dominated conversations regarding how this autumn’s projected swell in COVID-19 cases will unfold.
EG.5, a subvariant of XBB.1.5, was first identified in February, as noted by the World Health Organization. By routine predictive modeling, Health Canada currently estimates EG.5 to be the prevailing strain, responsible for an approximated 34 per cent of sequenced COVID-19 infections as of the week of Sept. 3.
The BA.2.86 Omicron subvariant was initially spotted in Denmark and Israel by mid-August, later appearing in the United States by Aug. 23, as stated by the Centers for Disease Control and Prevention. As of Sept. 12, 11 cases of the BA.2.86 subvariant have been detected in Canada, as confirmed by Tam.
According to an initial risk assessment of EG.5 by the World Health Organization on Aug. 9, this strain poses a moderate level of risk, demonstrating moderate transmissibility, reasonable resistance to vaccines, and minor severity of symptoms.
Recent Omicron subvariants, including EG.5 and BA.2.86, have not indicated any increase in virulence or severity.
The most prevalent symptoms of these subvariants, in line with other COVID-19 strains, span a runny nose, sneezing, a sore throat, and headaches. Less common symptoms comprise persistent cough, joint pain, chills, fever, dizziness, muscle pain, gastrointestinal complications, and an altered sense of smell.
Moderna’s new Spikevax XBB.1.5 vaccine, according to Tam, is expected to perform just as well against the two new subvariants. She recommends anyone who has not yet been infected with COVID-19 or received a COVID-19 vaccine in the last six months should consider getting vaccinated with this most recent COVID-19 vaccine formulation.
Concurrently, Pfizer-BioNTech and Novavax are seeking Health Canada’s approval for their respective XBB.1.5 COVID-19 vaccines.
Health Canada’s Chief Medical Advisor Dr. Supriya Sharma revealed that while clinical data looks promising, only time will tell how these variants will behave as they continue spreading. There is always a looming concern about the potential strain each seasonal wave of SARS-CoV-2 infections could exert on Canada’s already vulnerable health-care systems. However, Sharma conveys some amount of relief. “The primary concern was around the highly mutated BA.2.86,” she said, “but at this instant, it does not seem like it will become dominant.”