Cough, cough. Sniff, sniff. Americans are in for a different kind of October surprise this year: an early start to flu season.
The U.S. Centers for Disease Control and Prevention is out with new data that shows flu-related hospital emergency department visits are on the rise, as are hospital admissions, the number of people going to the doctor seeking care for influenza-like illness, and the percentage of people who test positive for flu. That's especially true in some western and southern states.
About 10% of tests are positive in the states of Arizona, California, Hawaii, Nevada and some U.S. Pacific island territories, according to the CDC.
That is significant because flu season typically begins when test positivity rates are at about 3%, said
Katelyn Jetelina, an epidemiologist who consults for the CDC and writes the Your Local Epidemiologist Substack.
"The West is clearly well on its way into the wave," she wrote. "The flu will slowly but surely move from the Pacific eastward in a sweeping motion. So, although rates are still relatively low in the Northeast, they will start increasing quickly soon."
In Michigan, the CDC still showed the spread of flu-like activity was "minimal" in the week ending Oct. 17, the most recent date for which data was available, but the curve shows an upward trend.
The Michigan Department of Health and Human Services' weekly Flu Focus report suggests a mutated H1N1 virus could be what's driving the early rise in flu activity nationally.
"Nearly all cases so far are Influenza A(H1N1), and most circulating H1N1 viruses carry a mutation called G155E. Studies suggest antibodies from past infections or vaccinations may not recognize it, especially in teens and young adults," the report says.
About 1 in 4 Michiganders got a flu vaccine last season, totaling roughly 2.7 million people — a drop of about 970,000 people compared with the 2021-22 season.
Health leaders say if you haven't rolled up your sleeve for a flu shot yet, now is the time to get vaccinated.
"Everyone 6 months of age and older is advised to get a flu shot. This year’s vaccine matches two of the three circulating strains very well," MDHHS reported. "Over the past decade, they’ve cut flu hospitalizations and deaths by 30-60%."
The CDC acknowledged that "every influenza season is different — some begin earlier than usual, others late," the agency wrote in an Oct. 23 post to its flu surveillance website. "Early-season influenza activity is currently higher than typically observed at this time of year."
It's unclear what that early start might mean for the rest of the fall, winter and spring when it comes to flu.
But the current data suggests people within certain age groups are getting hit hardest right now.
"There are some notable patterns," said Caitlin Rivers, an epidemiologist who directs the Center for Outbreak Response Innovation at Johns Hopkins University Bloomberg School of Public Health in an Oct. 25 post on her Substack Force of Infection. "Children ages 1-4 and 5-17 have the highest percent of visits to the ED for influenza, currently between 2-3%. However, this partly reflects the fact that adults visit the ED more often for other reasons, such as chronic illness, so flu makes up a smaller share of their visits.
"This is why we see a big flip when we look at hospitalization rates. Older adults, particularly those age[s] 75 and over, have the highest rates of influenza hospitalization by far, now over 6 per 100,000 and climbing. This is why it's especially important for older adults to get vaccinated as soon as possible."
Contact Kristen Shamus: kshamus@freepress.com. Subscribe to the Detroit Free Press.
This article originally appeared on Detroit Free Press: Flu wave hits U.S. early. What's happening in Michigan?
