COVID-19 cases in NYC show omicron infections may be plummeting

New York City's surge of COVID-19 cases fueled by the omicron variant appears to be falling just as quickly as it rose.

Tens of thousands of infections are still being reported every day, and the test positivity rate is still above 20%. However, after new cases increased 26-fold in just one month, they have now fallen by 57% over the last week, an ABC News analysis found.

After a single-day peak of ​​50,803 COVID-19 cases reported on Jan. 3, just 9,202 cases were reported on Jan. 14, according to data from the New York City Department of Health & Mental Hygiene.

In addition, hospitalizations are declining, and the number of wastewater samples that have detected the virus have also plunged.

"Infections are coming down, even visits to the emergency room are coming down," Dr. Ali Mokdad, an epidemiologist with the University of Washington's Institute for Health Metrics and Evaluation in Seattle, told ABC News. "And usually we see when there is a surge, we see visits to the emergency rooms going up."

Mokdad, who helps lead a model that projects COVID-19 cases around the country, added, "All the indications of the people being tested and found to be positive show that [omicron] appears on its way down."

On Dec. 2, the first case of omicron tied to New York City was reported in a Minnesota resident who had traveled to the Big Apple in November to attend an anime convention.

From there, COVID-19 cases began spiking. Within two weeks, the city was reporting an average of nearly 7,600 infections per day, up from 1,600 per day.

Studies have since shown that omicron is more likely to pass between vaccinated people than prior variants, though vaccines still dramatically reduce the risk of severe illness.

Coupled with the cold weather and people gathering for the holidays, Mokdad said it is no surprise the virus spread as quickly as it did.

Even coronavirus levels in wastewater samples were showing that a surge was coming, according to wastewater analytics company Biobot.

"The scale of the amount of virus that was detected in wastewater was far greater than any point in the pandemic, so much so that [the company] had to rebuild some of the graphs around the scales, because so much more virus was being collected more than any time," said Dr. John Brownstein, an epidemiologist who is a member of Biobot's board of advisers and an ABC News contributor. "It gave us that early sense that we were going to deal with this massive surge."

However, there are signs the city may have hit its omicron peak.

New York City has been reporting nearly 12 straight days of COVID-19 case declines and is averaging about 15,000 new infections per day, down from roughly 36,000 just two weeks ago.

In yet another sign that the city's surge may be ebbing, New York City no longer holds the nation's highest case rate -- Rhode Island now does, according to the Centers for Disease Control and Prevention.

Hospitalizations have also declined from an average of 992 new admissions on Jan. 6 to 496 as of Jan. 15, according to the city's health department.

Mount Sinai Health System, one of New York City's largest hospital systems, has seen new daily COVID-19 hospital admissions remain relatively flat over the last week to 10 days. About one-third of patients are admitted for other reasons and then test positive during their stays, Dr. Bernard Camins, medical director for infection prevention at Mount Sinai, told ABC News.

He said hospitalizations will not significantly come down until two or three weeks from now, because they are a lagging indicator.

"When people get sick enough with COVID, now they are going to come into the hospital, and it does take a delay," Camins said. "Sometimes people start having symptoms but they're not sick enough to need the hospital until Day 7 or 10 days later."

He added, "Eventually the ones who were coming into the hospital with 'moderate symptoms' or maybe severe enough to need oxygen, it does take them a few more days lag in terms of needing ventilators."

A rapid rise in cases followed by a dramatic decline is similar to what has been seen in other countries that detected omicron before the U.S.

In South Africa, where the variant was first identified, the surge looked like an "ice pick," according to CDC Director Dr. Rochelle Walensky. In early December, the country was averaging about 10,000 cases per day, quickly rising to 20,000 by mid-December.

But, by early January, when New York City was experiencing its peak, the average number of COVID-19 infections in South Africa had already fallen to about 8,000 per day.

"What we know and are certain about from data from South Africa and the U.K., when omicron takes hold in a location, it takes about a month to go up and a month to come down," Mokdad said.

Even though the surge is not entirely over yet, Mokdad said New York's decline is a signal for the rest of the country, with the Midwest about one week behind and the West Coast two or three weeks behind.

The University of Washington's own model suggests that the U.S. will peak at about 1.2 million cases Jan.17, and then all states will be on their way down by the end of January, Mokdad said, adding that he is still encouraging vaccination and mask-wearing.

"Everybody who's out and about will be infected by then," he said. "This is like infecting everybody out there, so basically, it's running out of people to infect and it's going to start coming down because there's no more people to infect."