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Covid-19 trends haven’t changed in weeks, and no one knows what’s next

It’s a dramatic improvement from this winter — there were four times as many hospitalizations and nearly six times as many deaths at the peak of the first Omicron wave — but still stubbornly high numbers.

And there are big question marks about what might happen next, as the evolution of the coronavirus remains quite elusive 2½ years into the pandemic.

“We’ve never really cracked this: why these fluctuations go up and down, how long they last, and how fast they fall off,” said Dr. Eric Topol, cardiologist and professor of molecular medicine at Scripps Research. “All these things are still a mystery.”

For now, BA.5 remains the dominant subvariant in the US, causing the most new cases, as has been the case since the last week of June.

Data from the US Centers for Disease Control and Prevention released on Tuesday shows that the Omicron offshoot accounted for 87% of new cases in the first week of August, up a few percentage points from the previous week.

This slight increase in prevalence is a sign that no other variants are outperforming it – and bodes well for future trends.

BA.5 “was very impressive because it’s so transmissible and it has so much immune evasion,” Topol said. But the plateau in hospitalizations is “encouraging” because it means the subvariant has likely worked its way through most hosts it can find.

“Right now the question is what comes when we descend from BA.5. That can take weeks.”

Forecasts from the CDC cast predict stable trends in hospital admissions and deaths over the coming weeks, and experts agree the worst of the wave is likely over.

But it’s buzzed along at a high level because it continues to find people whose immunity to vaccination or infection has waned over time — something that will continue to happen, said William Hanage, an epidemiologist and associate professor at Harvard TH Chan School of Public Health.

And with kids going back to school, a change of seasons and other variations on the horizon, it’s unclear when the plateau will drop — and by how much.

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“I would expect things to go back at least for the next month or so,” said Trevor Bedford, an epidemiologist and genomic scientist at the University of Washington’s School of Public Health.

“Of course there are other things waiting in the wings. If it’s not variant-driven, it’s going to be seasonal,” he said, with case numbers likely to increase as more people head indoors for colder weather.

Even if Trends aren’t improving as expected, but potential future waves are unlikely to be as devastating as Delta or the original Omicron variant.

Alpha, Delta, and Omicron “are cousins, not children,” Hanage said. They each had a significant impact on the population because they were so different.

But the change that has taken place this year – from BA.2 to BA.2.12.1 to BA.5 – is all “born out of Omicron” and the subvariants are much more similar to each other. If the next variant were as different as the move from Delta to Omicron, that would be “quite different” than last time, he said.

The CDC is expected to relax recommendations on Covid-19, including for schools, as early as this week

It’s not impossible, and a lot of attention is paid to the latest sub-variants that have popped up.

Over the past week, BA.4.6 grew from about 4% of cases in the US to just under 5%, according to CDC data.

Its mutations aren’t “of particular concern” when it comes to immune evasion, Topol said, but we just don’t know yet. Even a small increase in prevalence is growth, and “if it keeps growing, that means it has an advantage. The more it grows, the more we have to worry about it.”

Another Omicron fork, BA.2.75, didn’t make it into the CDC’s variant tracker. It accounts for less than 1% of cases in the US, according to gene sequencing company Helix.

But people are watching “with a certain level of concern” because there are more changes in the spike gene that could lead to greater immune escape or transmissibility, Hanage said.

Still, so much is unknown. Combinations of changes like this have sometimes led to the next worrying variant, and sometimes they’ve gone nowhere, he said.

Looking ahead, Hanage says “there will likely be one step forward and two steps back” when it comes to progress on the Covid-19 pandemic.

And if deaths stay above 400 a day for a full year, that’s more than twice as bad as the worst flu seasons in recent memory, he said.

“So those are numbers that we have at the moment, at a time when things are relatively good,” he said. “That’s something I don’t think a lot of people understand.”

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