A new strain of influenza has surged across the country following a busy holiday travel season, with flu activity at “high” or “very high” levels in 32 states and jurisdictions, according to a Centers for Disease Control and Prevention report.
Since the flu season began in October, at least 7.5 million people have contracted the illness, USA TODAY reports. Hospitalizations nearly doubled in just one week, climbing to 19,053 from 9,944 the week before, based on CDC data. About 3,100 deaths have been reported.
According to the CDC’s FluView Interactive Map, which monitors visits for respiratory illness with fever plus a cough or sore throat, Florida is seeing high activity. Colorado, Louisiana, South Carolina and New York have the highest number of cases.
What is the new flu strain?
Dubbed the “super flu,” the latest influenza strain, Subclade K (A(H3N2), J.2.4.1), is a mutation of the influenza virus. Influenza A(H3N2) viruses are the most frequently reported flu viruses this season.
It was responsible for earlier outbreaks in Europe, East Asian countries, and Canada. It was first seen in the U.S. as early as August, according to the CDC.
According to USA TODAY, health officials have expressed concern that the current flu vaccine may not be a perfect match for the new H3N2 mutation. Because it’s structurally distinct, subclade K may also be better at evading immune systems that have already developed protection against more familiar strains.
They stress that this year’s vaccine isn’t totally useless against subclade K and can still prevent serious illness.
What are the symptoms of the H3N2 flu?
Symptoms associated with H3N2 are similar to those of other influenza viruses and include:
How long does the ‘super flu’ last?
It can last from a few days to two weeks, according to the Cleveland Clinic.
When is flu season? When is the peak of flu season?
“The flu reporting year uses standard reporting weeks outlined by the Centers for Disease Control and Prevention (CDC), where every year has 52 or 53 reporting weeks. Though flu season ends May 17, 2025 (week 20), surveillance continues year-round,” the Florida Department of Health’s website says.
“Seasons vary in timing, severity, and duration. It is not possible to predict what each flu season will be like in Florida.”
Flu season typically begins around late September or early October, when temperatures start to cool, and usually lasts until the following summer, in May. Influenza season normally peaks in mid-to-late winter, from around December through February.
How to protect yourself from the flu
To start, experts strongly recommend receiving a flu shot, as it is the most effective way to prevent serious illness from the flu. Everyone aged 6 months and older is eligible for the influenza vaccine unless they have a specified medical condition, such as an allergy to its ingredients or a previous severe reaction to the vaccine.
The CDC also recommends taking everyday preventive actions to stop the spread of germs, giving these tips:
When is the best time to have a flu vaccine? Is it too late to get flu shot?
It’s never too late! You can get a flu shot at your convenience. There are no rules about when you can or can’t get a vaccine, but professionals typically recommend getting your shot in September or October.
“For most people who need only one dose of influenza vaccine for the season, September and October are generally good times to be vaccinated against influenza,” the CDC says. “Ideally, everyone should be vaccinated by the end of October.”
Contributing: Mary Walrath-Holdridge, USA TODAY, and Lianna Norman, USA TODAY NETWORK
This article originally appeared on Fort Myers News-Press: What is Subclade K? What to know about ‘super flu’ strain and its symptoms
Reporting by Samantha Neely, USA TODAY NETWORK – Florida / Fort Myers News-Press
USA TODAY Network via Reuters Connect
