As the United States grapples with its most severe flu season in a quarter-century, states like Michigan and Tennessee are experiencing unprecedented surges in influenza cases, hospitalizations, and related complications. The culprit behind this sweeping wave is a newly emergent strain known as H3N2 subclade K—informally dubbed the 'super flu'—which experts say is both more widespread and more severe than the typical seasonal flu.
According to WLAF News, Tennessee is currently reporting some of the highest flu case numbers in the country as of January 12, 2026. The story is much the same in Michigan, where the U.S. Centers for Disease Control and Prevention (CDC) has designated the state as having one of the nation’s highest levels of flu-like illness. The impact is staggering: Michigan hospitals reported 818 inpatients with influenza, including 759 adults and 59 children, as of January 12, 2026, Bridge Michigan reported. Furthermore, the majority of those hospitalized are 75 and older, with very young children—four years and under—making up the next highest group.
But the flu isn’t acting alone. Michigan also saw 540 hospital patients test positive for COVID-19 in the same period, compounding what Dr. Terry Matthews, CEO and medical director of Lansing Urgent Care, described as a "layer cake effect" of respiratory illnesses. "You couple (flu and COVID) with RSV, the common cold, and rhinovirus, and we’re a pretty sick state," Dr. Matthews told Bridge Michigan. This convergence of respiratory viruses has led to what some health professionals are calling a significant base layer of sick patients, with strep throat adding to the burden.
The rise in flu cases is being driven by the H3N2 subclade K strain—emerging after the 2025-26 vaccine formula was set, according to the Journal of the American Medical Association. This timing means the vaccine may not be a perfect match for the circulating virus, but experts still recommend getting vaccinated. Dr. Kristin Mondy, Chief of Infectious Diseases at the University of Texas at Austin Dell Medical School, explained to KBTX: "I’ve had a lot of people ask me, ‘is it worth getting the flu shot with this super strain of the flu?’ And the answer is yes, it’s still worth getting a flu shot." She added that while the shot may not completely prevent the flu, it can reduce the severity of symptoms and help protect vulnerable populations.
Indeed, the numbers are sobering. The CDC reports that, as of early January 2026, flu cases nationwide have soared to 15 million, with 180,000 hospitalizations and 7,400 deaths. Since October 25, 2025, there have been 120,000 flu hospitalizations and 5,000 flu-related deaths in the U.S. The surge is not limited to one region; nearly every state is classified as experiencing "high" or "very high" levels of flu activity.
In Michigan, the situation is particularly dire. Dr. Teena Chopra, professor of Internal Medicine and Infectious Diseases at Wayne State University School of Medicine, told the university’s news outlet that this is "notably one of the most severe flu seasons." She elaborated, "With millions of flu cases reported nationally, both outpatient cases and hospitalizations are at record high compared to the same time last season." Dr. Chopra also noted that Southeast Michigan is seeing "very high" influenza activity, with over 90% of cases attributed to the H3N2 subclade K strain. Hospitalization rates are climbing, especially among unvaccinated children and older adults.
The moniker "super flu" has been attached to subclade K not because it is a wholly new virus, but because it spreads more rapidly and causes more severe disease in the elderly and very young children. Dr. Chopra explained, "Even though it has informally been called ‘super flu,’ it is not a new virus. It does, however, spread more rapidly and cause more severe disease in the elderly and very young children." She warned that serious outcomes can include pneumonia, respiratory distress, worsening of chronic respiratory conditions, severe pediatric illness, and even mortality.
Why are children so vulnerable this season? Dr. Chopra pointed to several factors: "Children often have less previous immunity from previous exposures, which makes them more vulnerable. Also, kids attend day care and school, where they have increased chances of exposure. Lastly, this year vaccination rates have fallen drastically in children, which further makes them more vulnerable."
Vaccination rates are indeed worryingly low. Less than 25% of Michiganders are vaccinated against the flu, and fewer than 10% are vaccinated against COVID-19, Bridge Michigan reported. Many patients believe that a flu vaccine received years ago still offers protection, a misconception that Dr. Matthews addressed bluntly: "They’re paying the price. They’re out of work, they’re miserable, their children aren’t going to school." State and federal health officials continue to urge vaccination for everyone six months and older, including infants and young children, to help stem the tide.
For those who do contract the flu, experts recommend a combination of self-care and vigilance. Raewyn Snodderly of Terry’s Pharmacy in Tennessee advised, "Isolate yourself if you become ill, hydrate, take acetaminophen and ibuprofen in rotation, and sleep propped up." Dr. Chopra echoed these recommendations, adding, "Stay home and rest, hydrate, use fever reducers, avoid exposing others, and consult a clinician if you have severe symptoms." The duration of symptoms can range from three to seven days, but cough and fatigue may linger for a week or more, and some individuals—especially those at higher risk—may experience prolonged recovery.
Preventive measures remain crucial. Frequent handwashing, staying home when sick, covering coughs and sneezes, avoiding close contact with those who are ill, and wearing masks in crowded indoor settings are all recommended. Dr. Mondy emphasized the importance of "common-sense things like washing your hands frequently if you feel sick," and urged people not to "bite it out and go to work" if they have a fever or symptoms. She also highlighted the need to protect vulnerable populations by staying away from them if you’re ill.
Medical professionals stress that while most people will recover with rest and fluids, certain warning signs—such as trouble breathing, chest pain, persistent vomiting, dehydration, confusion, or inability to wake—should prompt immediate medical attention. As Dr. Mondy put it, "Signs that are worrisome are signs that could indicate a complication, such as pneumonia, influenza A risk factor for pneumonia. So, if people start to get shortness of breath, whether they’re sitting or walking around, that would be concerning."
With the flu season expected to continue into February or later, health officials say it’s not too late to get vaccinated. The consensus among experts is clear: while the flu shot may not be a perfect match for this year’s dominant strain, it remains the best defense against severe illness and hospitalization. As the country battles the relentless spread of subclade K, those small acts—washing hands, staying home when sick, and getting vaccinated—could make all the difference.