Why omicron is overtaking delta — and what that means for our fight against COVID-19

In the battle of the variants, omicron is poised to win.

While delta has long dominated the bulk of Canada's coronavirus cases, the latest variant of concern is set to overtake other variants both here and abroad as it spreads through more than 60 countries around the world. 

Early evidence suggests omicron is more adept at infecting people who've already had COVID-19 or multiple doses of leading vaccines, and the heavily mutated variant also has an uncanny knack for transmitting between people in the same home. 

In other words, it's likely incredibly contagious, and capable of leaving delta in its dust. 

While there are hopeful signals that vaccination still protects against serious disease, with boosters offering a stronger shield against any level of omicron infection, multiple medical experts who spoke to CBC News warn it's time to buckle down for a tough stretch ahead — since this variant will find its way to the vulnerable, even if most Canadians who get infected are largely unscathed. 

"I don't think we've seen anything like omicron in this pandemic yet," said Sarah Otto, an expert in modelling and evolutionary biology with the University of British Columbia in Vancouver. "It's capable of taking over in a matter of a few weeks."

In the U.K., where omicron is on track to take over as case counts keep rising, top medical officials said Sunday that data on severity of these infections isn't yet clear, but hospitalizations tied to omicron are already happening.

A day later, the country reported its first omicron-linked death, as Prime Minister Boris Johnson warned of a "tidal wave" of cases.

WATCH | U.K. Prime Minister Boris Johnson notes the 'sheer pace' of omicron spread:

The variant is also surging in Denmark, while French hospital officials are warning of an omicron-fuelled wave next month.

The latest federal modelling data in Canada suggests countrywide coronavirus cases here could quadruple to 12,000 a day in January if "omicron successfully establishes." 

And the most up-to-date figures provided by Ontario's science table show omicron has a reproduction number roughly three times that of delta — and a doubling time for cases of only three days — with the variant already making up an estimated 31 per cent of that province's coronavirus cases as of Monday.

Just one day prior, omicron made up an estimated 20 per cent of reported cases.

WATCH | When could omicron become dominant in Canada?