US Flu Cases Reach Highest Level in 25 Years: Symptoms, Risks, and What to Do

Flu has gripped most states across the United States, with very high levels of activity as a new strain known as subclade K continues to wreak havoc. According to the Centers for Disease Control and Prevention, the country is at its highest levels of respiratory illness since at least the 1998 flu season. Experts are calling 2025-26 the worst year as far as the number of people affected with the flu is concerned. The CDC data says that around 8.2 per cent of doctor visits were for flu-like symptoms during the last week of the year. At the same point last season, which was also brisk, that number was 6.7 per cent. Most states that have reported high levels of flu activity are urging people to get vaccinated. The CDC says nearly all states are at high or very high levels of flu activity in the latest

data. Montana and Vermont reported low levels of activity, while South Dakota and West Virginia reported moderate levels. Nevada has not reported flu data this week, but showed high levels of flu activity in last week’s report, according to CNN. New York City is facing a record surge, with more than 4,500 flu-related hospital visits during Christmas week alone, a 24 per cent increase compared to the week prior. State health officials also reported more than 72,000 new cases over a seven-day period.

High rates of hospitalisations

The rate of hospitalisations due to flu is also not low. The cumulative rate is the third-highest by this point in the season since 2010-11, and doctors say it would only increase as more people get infected. The CDC has said so far at least 11 million people have been down with flu this season, with more than 1,20,000 hospitalisations and more than 5,000 deaths, which include nine children.

Flu vaccinations are significantly dropping.

Despite pleas from health officials, flu vaccinations have been dropping considerably among children, from a high of 53 per cent in 2019-20 to just 42 per cent this season. Doctors are worried that if things do not improve within the next two weeks, it may be too late to form immunity against the condition.

New flu strain subclade K to be blamed

Experts say the new flu strain, subclade K, is the reason for the intensity. The variant was first spotted in June, and it was then noticed that it was expanding rapidly during the Southern Hemisphere’s flu season and in several Northern Hemisphere countries. Scientists believe the subclade K virus is a shape-shifter, constantly mutating, and it comes in multiple forms. There are two subtypes of type A flu, and subclade K is a mutated version of one of them, named H3N2. That H3N2 strain is always harsh, especially for older adults. Subclade K’s mutations are not enough of a change to be considered an entirely new kind of flu. But they are different enough to evade some of the protection from this year’s vaccine.

Does subclade K make people sicker?

While the CDC says it is too soon to know how severe this season will be, the variant can lead to serious illness. Doctors say it causes extremely high fever, along with signs of a cold and flu. In the long run, it can totally damage your lungs as well.

Signs and symptoms of flu

Symptoms of the flu usually come on quickly and can include:

• High fever
• Chills
• Body aches
• Cough
• Headache
• Sore throat
• Runny and stuffy nose
• Tiredness or feeling run down
• Diarrhoea and vomiting