(NEXSTAR) - The flu virus is already hitting hard this season as a new variant spreads rapidly, but it's not too late to protect yourself, experts say.
Much of the concern this flu season is coming from the spread of subclade K, a subtype of influenza A. Similar subtypes have historically caused more hospitalizations and deaths than other strains.
In the United Kingdom, where flu cases have surged earlier than in the U.S., the virus is putting strain on the country's healthcare system. NHS National Medical Director Meghana Pandit said the "unprecedented wave of super flu is leaving the NHS facing a worst-case scenario for this time of year."
Experts fear low vaccination rates in the U.S. could lead to a historically bad flu season, but they say there's still time to course-correct.
"It is not too late to get a flu shot," said Dr. Andrew Pekosz, a virologist and professor at Johns Hopkins Bloomberg School of Public Health. "We're really at the beginning of the influenza season here in the U.S."
Since the early 1980s, the most commonly observed peak of flu season has come in February, but cases often ramp up starting in December.
While more research is needed on how the K subclade is unique, Pekosz said evidence from other countries show it's driving high case counts.
"It's very difficult to predict a flu season, but right now, we're at the beginning of what we probably are going to see as a pretty severe influenza season," he said. "We think this clade K virus is evading population immunity, meaning more people are susceptible to infection because it has mutations that are making it less able to be recognized by your body's immune system."
Even if the K subtype is more evasive, the vaccine still offers good protection, Pekosz emphasized.
"There are three different influenza strains that cause influenza. The vaccine covers all three. And with two of them, it looks like there's a pretty good match right now ... and we think it'll provide at least partial protection against this clade K H2N2 virus."
"We don't claim the vaccine to be perfect, it's not, [but] it works better at keeping you out of the hospital, the intensive care unit and helping keep you out of the cemetery," Dr. William Schaffner, a professor at Vanderbilt University's Department of Health Policy, told The Hill in November.
The Centers for Disease Control recommends vaccination against the flu for everyone 6 months and older. "Getting a yearly flu vaccination is the best way to reduce the risk from flu and its potentially serious complications," the agency advises.
It takes up to two weeks for the flu vaccine to take full effect.