Researchers are still untangling the risks of catching COVID over and over

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In the early days of the pandemic, catching COVID-19 felt like a grim game of Russian roulette.

Even young, healthy adults made headlines for ending up in ICUs. Long COVID appeared to strike at random. The virus wreaked havoc in long-term care homes, overwhelmed hospitals and led to a staggering number of deaths.

Fast forward to late 2023, and the situation is dramatically different.

A vast majority of the population has previously caught COVID, and for many, this virus is less of a threat. While hospitalizations linked to COVID are ticking up as winter approaches, they remain at far lower levels than the worst points in the last few years — and cross-country ICU admissions and life-support patients remain relatively stagnant.

There's also hopeful data suggesting rates of long COVID are dropping, while updated vaccines are set to provide a protective boost ahead of another busy respiratory virus season.

It all suggests we've tamed SARS-CoV-2 into submission. Yet this virus continues to circulate year-round, causing repeat infections, with few official measures still in place to curb its spread. Scientists warn the long-term toll on individuals' health remains somewhat uncertain.

"We're moving to a world where we're being asked to manage our own risk, so we should know what that risk is," said epidemiologist Caroline Colijn, a Canada 150 Research Chair in Mathematics for Evolution, Infection and Public Health at Simon Fraser University.

"And it's two things: The risk of getting infected and the risk of a bad thing happening to you if you get infected."

Around the world, scientists are striving to parse out just how risky individual COVID infections are at this point in time, though the population-level trends remain reassuring, multiple medical experts told CBC News.

It's at a transition point, said epidemiologist Bill Hanage, with the Harvard T.H. Chan School of Public Health, as we're heading toward a time when COVID becomes more of a background condition, without the same kind of "disturbing, wild fluctuations."

"That is not the same thing as it going away," Hanage said. "That's not the same thing as having no consequences."

But over the course of the last few years, the immunity landscape has shifted, given high rates of previous infections and multiple rounds of vaccinations.

That's led to a significant change in the severity of acute illness, said Dr. Lynora Saxinger, an infectious disease specialist with the University of Alberta. "The burden went from, at times, having most of the medical beds in a hospital filled with COVID patients to, sometimes, not having any COVID patients … or at the most, a handful," she said.