ELMHURST, Ill. — As the holiday season approaches, a surge of concern is sweeping through the medical community about a new flu strain known as subclade K. This strain has shown resistance to the current vaccine, posing a potential threat just as families prepare to gather for festive celebrations.

The Thanksgiving holiday, a time traditionally marked by shared meals and close gatherings, may also become a breeding ground for the flu virus. Experts warn that the flu could spread more easily during these celebrations, reminiscent of last year’s particularly severe flu season. Some health specialists fear this year might bring an equally challenging, if not worse, scenario.

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“Last year, right after Thanksgiving, it seemed like everyone had the flu,” recalled Dr. Kevin Emmerich from Endeavor Health Elmhurst Hospital. His experience underscores the rapid spread of the virus during the holiday period.

This year, subclade K has already wreaked havoc in countries such as Canada, the UK, and Japan, where it escalated to epidemic levels. These international outbreaks offer a glimpse into what might unfold in the United States.

“The experiences in other countries often serve as a reliable forecast for what we might face here,” noted Dr. Shivanjali Shankaran of Rush. “And the outlook isn’t promising.”

Dr. Shankaran further described the flu’s impact, saying, “It can feel like being hit by a car. It can cause severe body pain and, in some cases, lead to hospitalization or intensive care.”

Doctors say young children and older adults are especially at risk. And while doctors say the flu vaccine in the U.S. can help protect against more severe symptoms, only about one in five people in Chicago have been vaccinated.

“It does offer some protection, especially to people who are high-risk. So kids under 6 months and adults over 65 and people with cancer, transplants,” Emmerich said.

Experts say flu activity remains low in the U.S. so far, but it’s on the rise. So they recommend protecting yourself.

“Try to wear a mask, very helpful in preventing the viruses. Hand-washing, we always underestimate the importance of that,” Shankaran said.

It’s too soon to predict the flu season in the U.S., but experts say it’s more difficult because the Centers for Disease Control and Prevention was unable to track flu activity during the 44-day government shutdown.