Is omicron peaking?

The number of new COVID-19 cases in New York City rose more than twentyfold in December. In the past few days, it has flattened.

In both New Jersey and Maryland, the number of new cases has fallen slightly this week. In several major cities, the number is also showing signs of levelling off.

In Boston, the amount of the COVID virus detected in wastewater, which has been a leading indicator of case trends in the past, has plunged about 40% since its peak just after Jan. 1.

"We really try not to ever make any predictions about this virus, because it always throws us for a loop," Dr. Shira Doron, a public health researcher at Tufts Medical Center, told GBH News. "But at least the wastewater is suggesting a steep decline, and so we hope that means cases will decline steeply as well, and then hospitalisations and deaths will follow."

As Doron suggested, it is too early to be confident that the omicron wave has peaked even in areas with encouraging data — which tend to be the places where omicron first arrived in the US But there is good reason to consider that the most likely scenario.

"Looks like we may be cresting over that peak," Gov. Kathy Hochul of New York said this week.

A huge surge in cases that lasts for about one month, followed by a rapid decline, would be consistent with the experience in some places where omicron arrived earlier than in the US In South Africa, new daily cases have fallen about 70% from the mid-December peak. The chart showing South Africa's recent trend looks like a skinny, upside-down letter V.

In Britain, where pandemic trends have frequently been a few weeks ahead of those in the US, cases peaked just after New Year's and have since fallen somewhat.

With previous versions of COVID, such as the delta variant, the up-and-down cycles tended to last longer. Once an outbreak began, cases often rose for about two months before falling.

Scientists do not fully understand COVID's cycles, but the explanation probably involves some combination of the virus's biological qualities and the size of a typical human social network. After about two months, an outbreak of earlier variants began to burn out, much as a forest fire would.

Omicron is so contagious that it spreads more quickly. This rapid spread may also mean that it more quickly reaches most of the people who happen to be vulnerable to being infected by it. Omicron's brief boom-and-bust cycle is now "a familiar pattern," Joseph Allen of Harvard's School of Public Health said.

Ali Mokdad, a professor of health metrics sciences at the University of Washington in Seattle, told The Associated Press that he believed the true number of US cases — including those not included in any official tally — has already peaked, probably last week.

"It's going to come down as fast as it went up," he predicted.

A bumpy descent

To be clear, the current emergency is not on the verge of ending. Cases appear to be peaking only in places where omicron arrived early, mostly in the Northeast. In much of the country, cases are still soaring.

Already, some hospitals are swamped, and hospitalisation trends often trail caseload trends by about a week. Deaths trends tend to lag by another couple of weeks.

"It's going to be a tough two or three weeks," Mokdad said.

The US seems on course for a horrific amount of severe illness in coming weeks, overwhelmingly among the unvaccinated.

(Related: The CEO of United Airlines, Scott Kirby, said that while 3,000 employees recently tested positive for the virus, zero vaccinated employees were hospitalised. That is a big change. Before the company enacted a vaccine mandate, an average of more than one United employee each week was dying from COVID.)

Still, the beginning of the end of the omicron wave — if it turns out to be real — would be very good news.

It would mean that a milder variant had become the dominant form of COVID but was no longer causing a surge in cases and overwhelming hospitals. It would mean that tens of millions of Americans had built up additional immunity, as a result of an omicron infection. It would mean that the country would have taken a big step toward a future in which COVID is an endemic disease like the flu, rather than a pandemic that dominates life.

Lauren Ancel Meyers, who runs a COVID analysis project at the University of Texas, said people might soon look back on omicron as a turning point. "At some point, we'll be able to draw a line — and omicron may be that point — where we transition from what is a catastrophic global threat to something that's a much more manageable disease," she told the AP.

Of course, as we all should have learned by now, COVID could also surprise again. Another possibility, Meyers said, is that a dangerous new variant could emerge this spring. That outcome is both unlikely and plausible, which is always a tricky combination to understand.

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