Omicron could threaten COVID-19 immunity — but we're not going back to 'square one'

The omicron variant, now reported in multiple Canadian provinces and a growing number of countries worldwide, could threaten hard-won immunity to the virus behind COVID-19.

But global scientists say the world has a crucial head start on the latest variant of concern, thanks to early detection. And there's hope this highly mutated version of the coronavirus won't bring the world back to "square one" in this pandemic.

South African scientists quickly identified and alerted the world to the variant last week, finding a concerning number of mutations that could potentially impact the effectiveness of vaccines, the transmissibility of the virus and even the severity of disease. 

Immunologists and virologists say that while it will still take time to determine the variant's real-world impact, our immunity from vaccines and prior infection could take a significant hit if it takes off globally. 

"I wouldn't say that this one's going to put us back to zero," said Deepta Bhattacharya, an immunologist at the University of Arizona.

"But I do think that if it does spread, it's going to be a bigger problem than any of the variants we've seen before." 

Omicron contains more than 30 mutations in just the spike protein, the part of the coronavirus which helps it enter human cells.

Bhattacharya said while the mutations in the virus are concerning, it's important to keep in mind that the immune system is "multi-layered," and that protection from vaccines and prior infection against severe disease will likely still hold up against the new variant. 

"I think what we'll see is, in all likelihood, a pretty big drop in how well antibodies work," he said. "But then once we start to get some real-world studies into how things are doing, my guess is that the vaccines will still be doing a decent job in protecting people from getting really sick."

WATCH | Will our vaccines protect us against the omicron variant?

Canada could actually be in a better position than other countries if omicron spreads more widely, Bhattacharya said, because our delayed second dose strategy provided "more optimal" immune protection in the population.

"What's pretty clear is that that delayed spacing made a big difference in terms of antibodies and protection against delta — and I suspect it will be the same for omicron if it takes off," he said. 

"We've seen some other variants like this in the past that had us concerned — beta, I think, would be the best example — and it didn't really take off. It basically just got creamed by delta. And I think we still don't know the answer as to how this is going to go for omicron."

Several leading vaccine manufacturers have announced they're keeping a close eye on omicron and could have new vaccines ready in mere months, if needed.