By Michael Erman

NEW YORK, Feb 3 (Reuters) - Health experts are seeing signs of a much smaller wave of U.S. COVID-19 cases this winter than in previous years, which could put additional pressure on Pfizer PFE.N to find growth from its non-COVID treatments.

Pfizer, which reports financial results on Tuesday, has been under pressure from investors looking for an improved performance from its other products, such as its cancer drugs, to make up for COVID sales, which have crashed from their pandemic peak of close to $60 billion in revenue.

Investors have yet to be convinced. The stock is trading at around $26.50 - less than half its pandemic-era highs.

COVID products are still a profit driver for the company. Pfizer is forecast by Wall Street to report $5.3 billion in 2024 sales of its COVID antiviral treatment Paxlovid. They are expected to drop by about 25% in 2025.

Sales of Paxlovid and the COVID vaccine are expected to account for 16% of Pfizer's total revenue, estimated to be around $63 billion for 2024, falling to 13% of 2025 revenue, according to analyst estimates.

"They still had a pretty significant contribution of both vaccine and Paxlovid in the guidance. So I think there probably is some risk to that," said Jeff Jonas, portfolio manager for Gabelli Funds, which held about $50 million of Pfizer shares as of September.

Analysts expect earnings of 47 cents per share on $17.4 billion in revenue in the fourth quarter, according to LSEG data, both improvements from a year ago.

BMO Capital markets analyst Evan Seigerman said Pfizer's forecast is already conservative, and with COVID products no longer seen as a core business, investor reaction to lower volumes could be muted.

Chief Executive Albert Bourla, when he provided company forecasts in December, said Pfizer was still expecting a new wave of infections at the end of 2024 and into 2025, as it has seen in previous years.

But the COVID wave this winter has barely materialized, according to the latest data.

U.S. data on emergency department visits with diagnosed COVID-19 through Jan. 21, suggests that cases dropped significantly over the first three weeks of the year.

According to that data, cases peaked around Jan. 1, when about 1.4% of emergency department patient visits resulted in a COVID-19 diagnosis, far less than a year ago, when the diagnosis rate was 3.4%.

'WAITING FOR ANOTHER VARIANT'

The Centers for Disease Control and Prevention has not updated its COVID data since the administration of President Donald Trump ordered health officials to pause public communications.

But CDC wastewater surveillance also suggests that the amount of COVID-19 circulating around the U.S. is down since the beginning of the year, and significantly from a year ago.

Paxlovid prescriptions also peaked around the beginning of the year at less than a third of year-earlier volume, and have fallen for three weeks straight, according to IQVIA data from analyst notes.

Jeremy Kamil, a microbiologist at the University of Pittsburgh, said diminished COVID waves were the result of built up immunity after a huge percentage of people have had multiple infections, been vaccinated or both.

"That makes it harder for... this new pathogen to cause new enormous waves. It just bounces into one person, maybe infects a couple others, but then they don't spread it efficiently."

Johns Hopkins microbiologist Andy Pekosz said in an email that he doesn't see strong evidence for a new surge at this time. While it's too early to predict anything about this summer's potential wave, Pekosz said he is hopeful we will see a drop in COVID cases to "near nothing" during the spring.

Marc Johnson, a microbiologist at University of Missouri, said the most commonly circulating variant of the virus is nearly identical to the one that preceded it, which may be why cases are lower than during the three previous winter surges that were driven by new variants.

"(I'm) sort of waiting for another variant to come out of left field," he said, "but it hasn’t happened yet."

(Reporting by Michael Erman;Editing by Caroline Humer and Bill Berkrot)

((michael.erman@thomsonreuters.com;))