Omicron could threaten COVID-19 immunity — but we're not going back to 'square one'
Scientists warn variant mutations may heighten risk and urge Canadians to be cautious
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."
30+ mutations in spike protein
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."
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.
Moderna's CEO has also suggested that existing vaccines may be much less effective against the variant, though scientists are still waiting on hard data.
'Worst features' seen so far
Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization (VIDO) at the University of Saskatchewan, said while previous variants have had similarly troubling characteristics, the real scientific concern with omicron isn't just the number of its mutations, but where they are.
"Unfortunately, based on just the mutations, it looks like the omicron variant has some of the worst features of all of the variants of concern that we've seen thus far," she said.
"But it's also really important to note for people that we don't know exactly what's going to happen when all of these mutations get together, especially with all the other mutations that the omicron variant seems to have acquired."
Some of omicron's mutations have been associated with increased transmissibility, similar to alpha and delta, she said, while others have been associated with higher immune evasion, like with beta and gamma. And she notes delta has so far dominated all other variants.
"One of my biggest concerns is not so much that omicron is going to be more severe, but if omicron begins outcompeting delta," Rasmussen said.
"Especially if it's capable of causing more breakthrough infections that potentially could lead to another wave in many countries, particularly in the northern hemisphere, as we begin to go inside during the colder winter months and in preparation for the holidays."
Precautions will likely still work against variant
But as speculation about the variant spreads quickly alongside rising case numbers, experts say it's important to keep in mind that vaccines, public health restrictions and personal precautions will likely continue to work well to stop the spread of COVID-19.
"The key right now is we have to stick to the toolbox that we have developed over the last almost two years," said Dr. Abraar Karan, an infectious diseases fellow at Stanford University in Stanford, Calif.
"The advantage that we have, any time we see a new variant, is we're still dealing with SARS-CoV-2."
If research confirms early signals that omicron is more transmissible, the usual principles still apply: It's best to limit time in crowded indoor settings, and the use of masking and increased ventilation to prevent the airborne spread of this virus.
"Don't enter into a situation that is likely to be a danger for high transmission, meaning many unvaccinated people not wearing masks," said Rasmussen.
With the holidays underway, Karan said it's also crucial to layer precautions when gathering with family, like being fully vaccinated and adding in extra protections like mask-wearing — particularly around vulnerable groups who are at a higher risk of a serious infection.
"If you're indoors, around a lot of people, you have to think: 'Am I somebody, if I get COVID, is this very life-threatening for me?'" said Karan.
Wearing a high-quality mask, such as a KN95, would help stop aerosols or droplets from spreading, Karan noted, even if omicron proves more adept at latching onto human cells.
Unusual for variant to render vaccines 'obsolete'
Multiple experts also agreed that what's particularly crucial right now is for unvaccinated individuals to get their shots.
"At the individual level, if people are not yet vaccinated, they absolutely should get vaccinated," said Dr. Isaac Bogoch, an infectious diseases physician.
There are also other ways to expand vaccination coverage, he said, including that children five and up are now eligible for inoculation, and the potential for booster eligibility to expand to more older adults.
Even if omicron is capable of evading some level of immunity from the current slate of vaccines and antivirals, which targeted the virus's original strain, Rasmussen doesn't expect the variant to fully reduce vaccine-based protection.
"Your immune system is composed of more than just neutralizing antibodies, and we do have other antiviral therapeutics that are in the pipeline," she said. "So we're not back to square one."
Until we know more about what we're up against, Bogoch said we can't assume the worst.
"It would be extremely unusual for a variant to emerge that renders the protective benefit of vaccination completely obsolete," he said.
"This may be chipping away at some of the protective immunity, and we'll figure out if it does and to what extent in the days and weeks ahead. But some people are discussing that this is going to set us back to January of 2020 — and nothing could be further from the truth."