A year after one of the worst flu season in decades, there’s a new strain of influenza wreaking havoc in Texas and across the nation this winter.
“We’re seeing more patients than we’ve seen before,” says Edward Dominguez, MD, medical director of organ transplant infection disease at Methodist Dallas Medical Center. “And the vaccine might not be quite as effective against one of the circulating strains.”
Known as “subclade K,” this mutation branched off from the H3N2 family tree just as the current vaccine was being rolled out this summer, leading to an early spike in cases.
“This K strain seems to be a little bit more virulent, a stronger variety of influenza A than we saw last year,” Dr. Dominguez says.
That’s especially bad news because the 2024-25 flu season was brutal, with estimates of up to 82 million cases and over a million hospitalizations in the U.S. alone.
Dr. Dominguez shared his expertise on the latest cold and flu season, as well as some tips on how to stay healthy.
WHY FLU IS SO BAD
There are two reasons why flu season seems to be getting worse: one that we can control and one that we cannot.
The influenza virus evolves every year, sometimes in small ways called antigenic drift and sometimes in major mutations called antigenic shift, which can lead to a pandemic.
But don’t panic because subclade K represents only a drift away from the J strain of H3N2, which the current virus was tailored to prevent.
“We missed out on covering the right virus because we didn’t know there was going to be this change,” Dr. Dominguez says. “It’s still a protective vaccine, but it’s not as protective as it used to be.”
VACCINE STILL WORKS
That brings us to what we can control during what could be a second straight difficult flu season: getting vaccinated.
“The most important thing remains vaccination for influenza,” Dr. Dominguez says. “We can prevent hundreds of thousands of cases by vaccinating against influenza.”
Vaccination rates have dropped each year since the COVID-19 pandemic, and last year’s extreme flu season was a case in point. Only about 44% of adults and children in the U.S. were vaccinated against flu, well short of the 70% goal set by the Centers for Disease Control and Prevention.
Like last year, the flu vaccine may have missed the mark slightly, but it still could mean the difference between a three-day infection or a weeklong bout, let alone a trip to the hospital.
“We have been doing this for decades; we know the vaccine is safe,” Dr. Dominguez says. “There were several hundred deaths of children over the last couple of years from influenza. All of those were potentially preventable with the flu vaccine.”
Like young children, older adults are also especially vulnerable to severe flu infections. Texas has experienced a spike in emergency room visits caused by respiratory illnesses in November and December, topping 5,000 a week for three weeks in a row, according to the Texas Department of State Health Services.
OTHER INFECTIONS
Flu isn’t the only virus to blame for that spike in hospitalizations, Dr. Dominguez says.
“There are other viruses circulating right now: There’s enterovirus D-68, there’s respiratory syncytial virus, or RSV, and certainly there’s COVID-19.”
Like the flu, all of those viruses are covered by a vaccine, but doctors say getting a shot isn’t the only way to protect yourself.
From hand hygiene and keeping surfaces clean to coughing and sneezing into a tissue or the crook of your elbow, there are plenty of precautions to stay healthy. But there’s one way to stop the spread most effectively this time of year.
“Separate yourself if you’re sick and from anyone else who’s sick, especially if they have symptoms or a fever,” Dr. Dominguez says.
The holidays may be a time for togetherness, but don’t let the flu become the gift that no one asked for.
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