Experts wary of reports some Omicron cases are mild

AS `DREAM SCENARIO' OF A WEAKER COVID-19 VARIANT TANTALIZES, SCIENTISTS INSIST: `WE REALLY HAVE ZERO IDEA'

Sarah Otto's hope, her “dream scenario,” is that the Omicron variant does prove milder, that the variant rattling nerves, airlines and stock markets causes only mild disease, as some early anecdotal reports would suggest.

“That would mean let it run,” the University of British Columbia evolutionary biologist said. “Let it run its course and reach the world.”

“For the unvaccinated, mild COVID could train the immune system, much like vaccines,” Otto said. “For the vaccinated it would be like a natural booster.”

But she is ever so cautious. “I dare not even hope,” she said. “Hope isn't science.”

There are now reports of toddlers in hospital with Omicron, and while some South African doctors have said the cases they have seen appear mostly mild, with fever, cough and aches and pains, those cases involved mostly younger adults — university-aged students and people healthy enough to get on a plane. Not the medically fragile.

And while lower severity to Delta could be a good thing, the benefits could be washed away if Omicron spreads more easily or is better able to elude some immunity from vaccination or past infections.

“Maybe it causes half the amount of hospitalizations and deaths,” Otto said. But if there are many more infections, “that's still a lot of hospitalizations and deaths.”

Viruses new to humans tend to cause more severe disease at the early stages of an outbreak or pandemic, partly due to the fact we don't have pre-existing immunity, said Matthew Miller, an associate professor of infectious diseases and immunology at Mcmaster University in Hamilton.

“For viruses to evolve to become less severe there needs to be `selective pressure,'” Miller said in an email. If, like SARS-1, people get very sick, very quickly, they are less efficient spreaders, because they're too sick to go out in public. The virus peters out. But viruses aren't thinking animals. “They don't `care' about how sick they make people, as long as they can spread,” Miller said.

With SARS-COV-2, people can spread the virus quite efficiently already, even if they aren't yet showing symptoms or never do, meaning “it's not clear that there's much pressure on the virus to cause less severe illness,” he said.

Overall, SARS-COV-2 already causes fairly mild symptoms in most, though not for the elderly or those with chronic health problems, “and when there are high caseloads, the number of severe illnesses increases,” Miller said.

It will take weeks before scientists get a firm handle on how Omicron compares to Delta in terms of severity of disease, he and others said.