Health authorities in the United States are issuing urgent warnings as a newly identified and highly contagious strain of flu, dubbed a 'super flu', races across the country. The variant is causing unusually severe and prolonged illness, with doctors reporting week-long fevers and a worrying spike in hospital admissions, particularly among children.
A Never-Before-Seen Variant Takes Hold
The culprit is a novel variant of influenza A H3N2, identified as subclade K. Recent data from the US Centers for Disease Control and Prevention (CDC) shows 'very high' levels of flu-like illness in 32 states. Alarmingly, one in three flu tests is now returning positive, marking a 21 percent increase from the previous week and a staggering 76 percent surge compared to the same period last year.
Since September, influenza A has accounted for 97 percent of all flu samples in the US. Of those, 86 percent are H3N2, and a dominant 91 percent of the H3N2 samples belong to the aggressive new subclade K strain.
Severe and Unusual Symptoms
Doctors are reporting a shift in the typical pattern of symptoms associated with this flu season. High fevers that can persist for five to seven days are a major concern, often resisting common treatments like Tylenol or Motrin.
"More fever with the flu this year than people are accustomed to," Dr Mark Loafman, Chair of Family and Community Medicine at Cook County Health, told NBC 5 News. "The fever can last up to seven days... And that's worrisome. You feel ill, you feel sick and you worry that you're not getting better."
Beyond the relentless fever, patients are suffering from a persistent phlegmy cough, intense joint and muscle aches, vomiting, and diarrhoea. While gastrointestinal issues are more common in children, Dr Loafman noted that the new variant is sending more adults to emergency rooms with these problems.
Dr Juanita Mora, a national spokesperson for the American Lung Association, highlighted critical red flags. "It is one of those high fevers that won’t break," she said. She urged the public to seek emergency care for signs of shortness of breath, audible wheezing, or a cough that will not subside. Severe dehydration in patients who are too ill to eat or drink is another dangerous complication.
Impact on Children and Vaccination Advice
The virus is taking a significant toll on the young. At least nine children have died from the flu in the US this season, with those aged 5 to 17 experiencing the highest number of hospital visits related to the new strain. Illinois recently confirmed its first paediatric flu death of the season.
Experts stress that vaccination remains the most effective tool to prevent severe illness. Although the current annual flu shot was not specifically designed for the subclade K variant, it still provides crucial protection.
"There has been a lot of talk about the fact that the new variant is not well-covered by it. That is true, but you still get protection," explained Dr Loafman. "What we typically see, the folks that are sick, hospitalized, are those who were not vaccinated... It certainly mitigates the severity of illness." He added that it is not too late to get vaccinated, urging people to do so even if they have already been ill, as reinfection with different circulating strains is possible.
With students returning to school after the holiday break and people spending more time indoors, doctors like Dr Santina Wheat of Northwestern Medicine warn that cases could surge further in the coming weeks. "The question is, where will it peak?" Dr Loafman asked, noting that the current surge has not yet reached its zenith.
