The flu constantly morphs and mutates. Often, it surprises researchers a little.
This year, the virus is surprising them a lot.
They are bracing for a brutal season, driven by a new and alarming variant that is expected to circulate widely.
The main version of flu spreading in the United States right now is H3N2 subclade K. H3N2 is a common strain, but the specific type of it circulating now — subclade K — is what’s new. The variant has several mutations that differentiate it from previous versions, making it a “cousin of what we’ve always had,” said Dr. Scott Roberts, an assistant professor of infectious diseases at the Yale School of Medicine.
“I wish it were a sibling,” he said. “But it’s not.”
It isn’t clear yet whether the subclade K can cause more severe disease than past H3N2 variants, said Scott Hensley, a professor of microbiology at the University of Pennsylvania Perelman School of Medicine who studies the flu.
But the virus will likely spread more than in previous years, leading to more infections overall, he said, because it may be more adept at avoiding immunity from vaccines and previous infections.
Last year’s flu season was the roughest in nearly a decade. “We generally don’t have two bad flu seasons back to back,” said Dr. Roberts. “But a lot of us are concerned that with this new, slightly more-mutated-than-usual subclade K strain, that we may see that.”
This year, the flu hit earlier — and cases have skyrocketed — compared to previous years in Japan, Australia and the United Kingdom, key warning signs that things might get bad in the United States.
Data from the Centers for Disease Control and Prevention shows that while cases of the flu are about at the level researchers would expect for this time of year, the virus is steadily spreading.
“What’s clear is that influenza activity is picking up as we speak,” Dr. Hensley said.
Flu cases are most likely to peak in January or February, he said, fueled by an anticipated surge after winter travel and holiday gatherings.
Is the vaccine still effective?
Because this strain has evolved so much, some worry that this year’s flu shot might be less effective than doctors had hoped. But the shot still confers some protection that can help prevent people from getting seriously sick.
Dr. Hensley’s lab is testing whether people who got their flu shot this year can produce antibodies to fight the new variant. Preliminary results are encouraging: “There may be less of a vaccine mismatch than many people initially believed,” he said.
Early data out of England from this year also showed that the vaccine was around 70 to 75 percent effective at preventing flu hospitalization in children, and around 30 to 40 percent effective at doing so in adults.
People should still seek out a flu shot if they haven’t gotten one yet, to lower their risk of getting seriously ill, said Seema Lakdawala, an associate professor of microbiology and immunology at the Emory University School of Medicine.
What do we know about symptoms and treatment?
While vaccination is the best way to protect yourself, doctors also recommend basic precautions.
“The vaccine is your armor,” Dr. Lakdawala said. “It’s going to prevent you from getting badly beaten. But it’s not going to get you to win the war.”
Frequently washing hands, wearing a mask in crowds and improving ventilation as much as possible — by opening windows, if it’s not too cold, or running air purifiers — can minimize the risk of catching the flu. So can disinfecting hard surfaces like phones, doorknobs and countertops, where the flu virus can linger for over a day.
The flu tends to come on faster than other respiratory viruses: Patients often describe feeling like they’ve been hit by a truck, instead of the gradual progression of runny noses and aching throats that can come with Covid. Fevers, congestion, chills and full-body aches are all signs of the flu.
It’s tricky to distinguish flu symptoms from those of other common respiratory illnesses without taking a test. There are now combination at-home tests that detect both Covid and the flu. These are particularly helpful because the results can help you determine if you should take an antiviral treatment, like Tamiflu, which can help people recover from the flu a bit faster. These medications work best if people take them soon after they get sick. Some doctors also prescribe antivirals preventively to people who are at high risk for the virus if they are exposed.
Dani Blum is a health reporter for The Times.
The post What to Know About the New Flu Variant appeared first on New York Times.
