Flu season could linger into spring as doctors warn of second wave on the way

Health experts are warning that the 2025-2026 flu season isn't over yet. In fact, people should prepare for the virus to linger well into the warmer months, according to Dr. Michael Glazier, chief medical officer and pediatrician at Bluebird Kids Health in Florida.

The current season is tracking with historical trends, the doctor said, as influenza A typically strikes first and most aggressively.

"The 2025-2026 flu season has followed this pattern, with influenza A cases presenting earlier in the season and causing the majority of illnesses," Glazier told Fox News Digital.

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"Now, however, in the middle of February, we are seeing the emergence of influenza B cases, in addition to the continued predominant presence of influenza A, which is not unusual, and which will most likely continue into the spring months," he added.

While the timing of the waves is typical, the intensity is not. This year has been marked by a new influenza A H3N2 variant known as Subclade K. 

This strain has proven particularly difficult for several reasons, according to Glazier. Its newness means the population has very little defense built up from previous infections, and there has also been a decrease in vaccinations nationwide.

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The current vaccine has also shown to have decreased effectiveness against this specific strain.

"Although this was anticipated to be a more moderate flu season compared to recent years, the severity assessment determined by the CDC now ranks this as a high severity season for children," Glazier cautioned, noting that approximately 60 pediatric deaths have already been attributed to the Subclade K strain this year.

Glazier said it is "absolutely" not too late in the season to get the flu shot.

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"Even if you experienced an earlier influenza A infection, you can still get an influenza B infection," he said.

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Vaccination remains the best tool to minimize the duration and severity of the illness, even if the vaccine isn't a perfect match for the circulating strain, experts say.

Symptoms of spring allergies can differ from signs of the flu, Glazier said.

The flu is characterized by high fever, chills, body aches, night sweats, headaches and stomachaches, symptoms that are not caused by seasonal allergies.

Glazier urges parents not to ignore persistent or recurrent fever, especially if it doesn't respond to acetaminophen or ibuprofen. He also emphasizes monitoring hydration in children.

"Children become dehydrated more easily when sick compared to adults, and this worsens symptoms," he said.

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Adequate rest, hand hygiene, hydration and nourishment help bolster the body’s immune system and defense against viruses, the doctor added.