Omicron completely changed the pandemic. Are we prepared for what's next?

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Omicron completely changed everything we thought we knew about COVID-19 when it unexpectedly emerged a year ago and rapidly spread around the world within weeks — and there's still so much uncertainty around what it could do next. 

The devastatingly infectious variant upended our prior understanding of what the virus was capable of and how to effectively control it, and opened the door to previously unheard of levels of COVID-19 transmission, seemingly overnight.

"Omicron was a giant step in the wrong direction of where we wanted to go," Dr. Anthony Fauci, the outgoing director of the U.S. National Institute for Allergy and Infectious Diseases (NIAID) and the chief medical advisor to the U.S. President, told CBC News in an interview.

"It was highly significant in changing the pandemic because it really was quite different from the emergence of other variants which actually were in many respects closely related [to each other]," he added. "Omicron was a truly aberrant variant … it veered way off."

Fauci said that because it was so far removed from previous variants, Omicron had the innate ability to evade the immune protection from prior COVID infection and vaccination — and left us extremely vulnerable to massive amounts of transmission.

"Omicron changed the game," Dr. Maria Van Kerkhove, an infectious diseases epidemiologist and the World Health Organization's COVID-19 technical lead, said in an interview with CBC News.

"The sheer volume of cases that countries experienced and how each of the waves were synchronous around the world — we didn't see that before."

But could more have been done to slow the spread of Omicron and its highly contagious subvariants, or to stop them altogether? Will our population immunity hold up to its next moves? And are we better positioned now for the next Omicron-like variant? 

These aren't easy questions to answer, but some of the top global infectious disease experts, epidemiologists, virologists and immunologists on the front lines of the pandemic have weighed in on what we've been through with Omicron and what we can expect next.

Bill Hanage, an epidemiologist at Harvard's T.H. Chan School of Public Health in Boston, said when Omicron first emerged many experts were cautiously optimistic at the time due to the immunity in the population and the fact children were soon eligible for vaccination."And then Omicron came along and flipped the script," he said.

"Less than a month after it was first reported, it was the majority of cases here — and that's just extraordinary." 

Van Kerkhove said it was quickly clear Omicron was distinct from other variants like Alpha, Beta and Delta because of the dozens of mutations it had that allowed it to spread much more effectively, leading the WHO to almost immediately classify it as a variant of concern.

"The numbers of cases were extraordinary," she said. "And while we did see less rates of hospitalization of Omicron compared to Delta, in some countries deaths were higher during Omicron than in Delta because there were so many people that were infected."