Superflu Surge: Here Are the Syptoms And How To Treat the Aggressive Flu Strain

With winter in full swing, health officials are sounding the alarm on a new 'super flu' strain called A/H3N2 or the subclade K. It is more aggressive compared to other versions of the flu that we have seen lately and is now the top cause of illness in the United States and spreading globally.

While the super flu is a common illness during the winter season, experts said that subclade K is behaving differently and is now triggering early outbreaks. They said it is showing an intensity that has not been seen in years. It was reported that this new version of the flu is highly contagious and currently sweeping over the country.

Where the Strain is Hitting Hardest

The H3N2 flu mutation is causing a massive spike in cases around the world. In the US, the virus is moving so quickly that many hospitals are struggling to keep up with the huge number of people coming in.

Earlier this month, the World Health Organization reported on the outbreak, stating, 'Although global activity remains within expected seasonal ranges, early increases and higher activity than typical at this time of year have been observed in some regions.'

WHO added, 'Seasonal influenza viruses, including A(H3N2) viruses, continually evolve over time. Since August 2025, there has been a rapid increase of A(H3N2) J.2.4.1 alias K subclade viruses detected from several countries based on available genetic sequence data.'

In any case, the CDC just confirmed that the flu is spreading much faster across the U.S. In their latest update from mid-December, they ranked each state by how much flu-like illness they are seeing—ranging from 'very high' to 'minimal.' Here are the places where the flu is currently hitting the hardest:

Very High (Level 1) - New York City
Very High (Level 2) - New York State
Very High (Level 3) - New Jersey, Rhode Island, Louisiana, Colorado
High (Level 1) - Massachusetts, Connecticut, Michigan, Idaho, South Carolina
High (Level 2) - New Mexico
High (Level 3) - Washington, DC, Maryland, North Carolina, Georgia

The situation is just as bad in other parts of the world. The WHO reports that this H3N2 strain makes up nearly 90% of all flu cases in Europe. The UK, Ireland, and Serbia are seeing the most people sent to the hospital - in fact, hospitalisations in these regions surged by more than 50% in just one week.

'The United Kingdom got hit pretty hard by this, as did Europe and Australia,' Neil Maniar, director of the master of public health program at Northeastern University, said. 'I think that's a pretty good harbinger of what we are likely to see here. This is going to be a very difficult flu season.'

Symptoms of A/H3N2

The A/H3N2 often shows signs of an ordinary flu but most patients experience a sudden onset of symptoms. They attested that one moment they are fine and then suddenly, they feel extremely unwell.

Medical doctors further said that subclade K often starts with a more intense symptoms compared to the previous strains. Here are the main common symptoms to watch out for as they are more intense than a typical cold:

Sudden high fever and chills
Intense body aches
Headache
Sore throat
Persistent dry cough
Runny or blocked nose
Fatigue and weakness
Loss of appetite

Less Common Symptoms

Vomiting or loose stools (more common in children)
Chest discomfort
Red, watery eyes
Dizziness due to dehydration

How to Treat Subclade K

Currently, there is no basis to say that A/H3N2 K is more lethal than others and to clarify - its high transmissibility only means that a lot more people are getting sick at the same time. Luckily, this is a treatable illness. Most people with this flu get better by simply resting at home and taking basic medicine such as paracetamol.

The main goal is to make the patient feel more comfortable, keep the fever down, drink plenty of fluids, and make sure the symptoms don't turn into something more serious. Apollo Hospitals suggests these treatments:

Rest: Complete rest in the first 3 - 4 days
Hydration: Drink warm water, soups or teas to avoid fluid loss
Steam inhalation: To ease throat congestion and alleviate cough
Saline nasal drops: For blocked or dry nose
Humidifier: Keep the air moist with a humidifier to make breathing easier

For medications, take paracetamol to lower fever and manage body aches. Doctors may also prescribe Antiviral medicines like Oseltamivir within 48 hours of symptom onset as this is the time when it is most effective. Cough medicine is also used for treatment and doctors will pick medication based on age, symptoms, and overall health.