This winter’s craze influenza and Coronavirus disease Data released this week by the U.S. Centers for Disease Control and Prevention show that the pandemic has yet to hit much of the country, and trends so far are a fraction of what they were this time last year.
“COVID-19 activity remains low and stable in most areas. Seasonal influenza activity in children has increased slightly but remains low nationwide,” the CDC said in its report this week. weekly report Information about the two people Virus.
The agency’s update usually comes out each week by Friday, but it was delayed until after the weekend because of the Thanksgiving holiday.
Is the flu back on track?
By this time last year, data tracking flu outpatient visits in places like emergency rooms and doctors’ offices had climbed above the agency’s baseline for the season. The latest reports this year suggest that flu cases are only now starting to cross that threshold.
“We may be a little later than last year, we may be a lot later than the year before, but those years are unusually early,” said Justin Lessler, a professor of epidemiology at the University of North Carolina and a disease forecaster.
Lessler said this year’s data looks “much closer to what people would expect from a normal flu season before COVID-19.” Pandemicwhen measures to contain the outbreak disrupted seasonal patterns of influenza and other respiratory bacteria.
The number of people hospitalized with the flu each week is down about five times compared to last year. Flu-related emergency room visits among school-age children have increased, but are still less than a third of what they were this time last year, according to the CDC.
One important factor that could affect this year’s numbers is people’s immunity to the last two waves of influenza, and Vaccination.
Epidemiologist Sean said: “We’ve had two pretty significant seasons, which could lead to this delay. The question, of course, is whether that means we have a delay, or a milder season. In this At one point, it does feel a little iffy.
Models of this year’s flu season collected by different experts make different assumptions about the country’s flu immunity as they try to show different scenarios for this year’s flu season.
Trulove, who also helps lead the CDC-funded Disease Forecasting Network, agrees that this year could mark a “return to normalcy” for influenza.
“That being said, influenza is never consistent. We have early seasons and late seasons. So it’s hard to say exactly what that means, and everything is a little weird post-pandemic in terms of scale and timing,” he said. Rouloff said.
Watch for another COVID-19 wave
Several COVID-19 trends tracked by the CDC also remain below levels recorded at this time in 2023.
Nearly all states have “low” or “very few” COVID-19 emergency room visits since later this year summer wave Viral. Virus levels in wastewater are at “lowest” levels in all regions compared with “high” levels at this time last year.
“Does this mean that enough immunity was built up during the summer wave that we won’t see a winter wave? Does it mean that the winter wave is going to come, but it will be later, maybe a little smaller,” Lessler said.
Both Truelove and Lessler said a major “data gap” in comparisons to previous seasons is the lack of nationwide data on COVID-19 hospitalizations during the summer peak.
The pandemic-era emergency requirement for health care providers to report COVID-19 hospitalizations lapsed earlier this year and was only recently reinstated under new rules issued by the Centers for Medicare and Medicaid Services.
Other factors confusing the data include changes in how people test for and seek care for COVID-19 infections.
Another huge unknown is the evolution of SARS-CoV-2, the virus that causes COVID-19. Most of the currently circulating variants are mixtures of closely related variants like XEC and KP.3.1.1.
“Just like with the flu, we don’t know how quickly the coronavirus will evolve away from our immune system on average as it stabilizes,” Lessler said.
Early data released by Ohio State University researchers last month found that XEC appears to be more contagious than the parental variant shared upstream of KP.3.1.1, but not significantly more contagious than its siblings.
“I actually think things have stabilized after this year. We’ll see what I think after the season. But right now, I’m not so sure,” he said.
Other respiratory bacteria on the rise
While COVID-19 and influenza remain at unusually low levels nationwide, rates of at least other germs spread through coughs and sneezes remain high.
CDC data on emergency room visits for Mycoplasma pneumoniae, sometimes called “walking pneumonia,” has increased in recent weeks especially babies.
cases in this year’s whooping cough wave, or pertussisalso continues to accelerate in several states across the country.
The agency counted 577 cases of whooping cough infection nationwide in the week ending November 23, about 33% higher than last week’s figure. This is higher than the record peak of whooping cough in 2014, when 326 weekly infections were reported in late December.
Ohio continued to have the most whooping cough cases last week, with 66 reported cases.
The CDC’s “Acute Respiratory Illnesses” metric, which compiles levels of patients visiting emergency rooms for a range of cough and cold illnesses, including influenza and whooping cough, counts “moderate” rates in 14 states, including Ohio. level.
