The NHS has issued an urgent UK-wide 'stay at home' alert as
winter viruses, including the
H3N2 strain, are
spreading rapidly across the UK. In a recent X post, the health service also urged people to 'cover your nose and mouth' and to 'avoid contact with other people'.
Flu season has arrived sooner and is more intense this year. In the latest UK Health Security Agency (UKHSA) weekly report, it says influenza activity has increased and is now circulating at medium levels. It adds that emergency department (ED) attendances for influenza-like-illness (ILI) increased.
"The number of
influenza-confirmed acute respiratory infection (ARI) incidents increased," it continued. "Of influenza viruses subtyped at the UKHSA Respiratory Virus Unit, the
majority were A(H3N2)."
The H3N2 strain is currently the most dominant flu strain circulating in the UK during the 2025/2026 flu season. According to the UKHSA, a specific subtype of H3N2, known as subclade K, is responsible for the majority of recent cases, placing a significant strain on health services.
Besides using a tissue to cover your mouth and nose when you cough or sneeze, wearing a face mask can help significantly stop the flu and other respiratory viruses from spreading. They do this by blocking infectious droplets, which protects both the person wearing the mask and others around them, especially if someone is sick or in crowded places like
hospitals.
Masks serve as a barrier that keeps germs from moving through the air when you cough, sneeze, or talk. This makes them a valuable tool for maintaining everyone's health during flu season, according to guidance from the UK Health Security Agency (UKHSA).
On X, the
NHS said this morning (December 8): "If you have flu, there are some things you can do to help get better more quickly. Flu will often get better on its own, but it can make some people seriously ill. It's important to get the flu vaccine if you're eligible."