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What Canadian health officials know so far about the Omicron variant of COVID-19

Public health officials warn the Omicron variant could propel an enormous spike in COVID-19 cases over the next few months. But there's still a lot scientists need to learn about the latest mutation.

Public health officials warn the Omicron variant could propel an enormous spike in COVID-19 cases over the next few months. But there's still a lot scientists need to learn about the latest mutation. Here's what Canadian public health officials know about the variant so far: 

Prevalence 

— Almost 350 confirmed cases have been reported in 11 provinces and territories. Increasing numbers of cases are not linked to travel, pointing to community transmission in several parts of the country with outbreaks in multiple settings.

— The World Health Organization said Omicron has been reported in 77 countries worldwide but is likely already in most countries, even if not yet detected.

Transmissibility 

— Omicron has potential to spread more quickly than Delta, which was already highly transmissible.

— Canada's chief public health officer Dr. Theresa Tam says aerosol transmission is a main route of spread, and said to "think of it like smoke in the room: those closest to the source will inhale more." As a result, masking and ventilation are "very important."

— It's suspected that the incubation period for the Omicron variant may be a little bit shorter than for the other variants, but Tam says that is still under investigation.

Severity

— It's not currently known whether Omicron carries a higher or lower risk of severe illness or death. 

— Some of the current COVID-19 treatments may be less effective against Omicron than against other variants.

— Larger numbers of cases could impact health-care capacity. If it's assumed Omicron is three times more transmissible than Delta and becomes the dominant strain, the federal modelling has suggested the number of daily cases in Canada could explode to 26,600 by mid-January from about 3,300 currently.

Immunity

— Being fully vaccinated and then getting a booster shot is expected to reasonably protect against infection and likely offers strong protection against severe illness. However, experts say that must be combined with layers of public health measures and individual precautions.

— Omicron cases have been detected in both vaccinated and unvaccinated people, as well as in previously infected people.

(Source: Public Health Agency of Canada)

This report by The Canadian Press was first published Dec. 17, 2021.

The Canadian Press