Number of new flu cases dropping in New York

After a flu season that started fast and furious, the number of new cases in New York has steadily declined for almost a month.

But infectious disease doctors say it is possible that cases could tick up again, especially if another strain of flu takes hold.

The peak of the season so far took place the week ending Dec. 10 when 52,936 new lab-confirmed cases were reported in New York, according to the state Health Department.  By the last week of December the number had dropped to 22,905. More than 4,000 of those cases were on Long Island.

During the week ending Jan. 7, the latest period for which statistics were reported, there were 14,656 lab-confirmed flu cases in the state with 2,563 on Long Island.

Last year, doctors were surprised by a late-season flu peak that extended the season until June. That came after a season in which flu had all but disappeared as people hunkered down and masked up in the first year of the pandemic.

“Those of us who do what I do have kind of an odd saying: When you’ve seen one influenza season, you’ve seen one influenza season,” said Dr. Susan Donelan, medical director of Healthcare Epidemiology at Stony Brook Medicine. “Because they really can be so different.”

Flu cases along with respiratory syncytial virus

The warning signs came early with higher than average flu numbers that coincided with an early rise in respiratory syncytial virus in young children as well as the ongoing COVID-19 pandemic.

By the start of November, there were more than 14,000 lab-confirmed cases of flu across the state, including more than 2,300 on Long Island — the highest seen for that time period in over a decade.

They seemed to double by the week, jumping from 15,450 on Nov. 19 to 27,164 on Nov. 26 and 44,413 on Dec. 3 before peaking at 52,936 on Dec. 10.

Donelan said she saw a small rise in cases not long after school started in September, and students were no longer required to wear masks. It continued around Halloween, as people started gathering inside for celebrations.

“We knew we were in for a bit of a whammy and it didn’t disappoint,” she said.

By comparison, lab-confirmed flu cases for the same period around the Dec. 10 peak were 4,770 for the 2021-2022 season, 162 for the 2020-2021 season and 1,838 for the 2019-2020 season.

Lack of population immunity

Andrew Pekosz, professor and vice chair of the department of Molecular Microbiology & Immunology at the Johns Hopkins University Bloomberg School of Public Health, pointed out that having unusually mild flu seasons during the pandemic led to a lack of population immunity and the virus spread earlier than expected.

The Centers for Disease Control and Prevention estimates that so far this season there have been at least 24 million illnesses, 260,000 hospitalizations and 16,000 deaths from flu. There have been 79 pediatric flu deaths this year including six in New York.

“It is important to note that flu is still pretty high in most parts of the country,” Pekosz said. “So while it's coming down, I want to emphasize that it's not something we should forget about because there's still a lot of influenza and there's still some hospitals that are being swamped by COVID-19 and flu patients.”

Virtually all of the flu viruses lab tested this year are Influenza A, with less than 1% being Influenza B, according to the CDC.

Still within Influenza A and B are various subtypes that could emerge as dominant as the season progresses. Since the start of the season, the CDC said about 77% of Influenza A viruses that were subtyped were A(H3N2) and about 23% were A(H1N1).

For lab-confirmed Influenza A cases reported for the week ending Jan. 7 and subtyped, A(H3N2) were 71.6% and A(H1N1) were 28.4%.

And for that same week ending Jan. 7, tested specimens showed 1.4% were Influenza B and 98.6% were Influenza A. 

“Usually when we have two flu peaks, different viruses are driving those two flu peaks,” Pekosz said.

Donelan said there are often “multipronged surges or multiple surges” during a flu season depending on the strain that is circulating.

Fewer people got flu shot

Experts also believe another factor in this year’s flu season was that fewer people got their annual flu shot.

Some CDC data showed that by the end of October, vaccinations in medical offices and pharmacies for adults was down 15% but by Dec. 17, that gap may have been narrowed to 2%. More promising survey information from Jan. 6 suggests flu vaccine coverage for adults is up 4.1% from the same time last season, the agency reported.

About 47% of children have been vaccinated this year, a roughly equal percentage to the same time last year.

But fewer pregnant women received their flu vaccines — about 43.5% by the end of November. The CDC said this was an 11.8% drop over November 2021 and 18.6% drop from November 2020.

“We’re certainly not out of the woods yet,” she said, adding it’s not too late for people to get the flu shot.

“It’s only too late when flu is no longer circulating in the community,” she said. “We've got a lot of time between now and then to get vaccinated and keep ourselves as healthy as possible.”

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.