British Medical Journal
November 12, 2025
England is facing one of the toughest ever winters in its history as an early wave of flu sweeps the nation, health officials warn. Flu rates have started climbing much sooner than usual this year, driven largely by cases in young adults and schoolchildren. And experts warn that the H3N2 strain, currently dominant in cases in England, mutated seven times over the summer, making it more severe than normal. Amid growing concern that hospitals will be overwhelmed this winter, health officials have urged all eligible groups, including people over 65, people with certain long term conditions, pregnant women, and children, to get vaccinated.
The version of H3N2 that’s circulated worldwide this year “acquired 7 new mutations over the summer. That “means the virus is quite different to the H3N2 strain included in this year’s vaccine. The U.K. is heading “into what looks set to be a cruel winter, with flu cases being triple what they were this time last year. It’s picking up in Canada, too. H3N2 is generally thought to cause more illness and be worse for older adults than other strains. Japan is also experiencing an unusually early and harsh flu season that’s “unprecedented.
The Centers for Disease Control and Prevention hasn’t provided a detailed, national report on flu activity since Sept. 26th because of the government shutdown.
Will this year’s flu shot be helpful?
Global health officials and drugmakers select which viral strain to include in fall flu vaccines for the Northern Hemisphere each year in February, based on which types are circulating in the Southern Hemisphere. This year’s flu shots protect against three strains of influenza, including two types of influenza A and one type of influenza B. The annual flu shot doesn’t prevent people from getting infected with the flu. It’s mainly used to lessen the severity of the illness. Last year, the vaccine was up to 55% effective in keeping adults with the flu out of the hospital.
There are multiple types of flu; H1N1 causing the swine flu, which caused a pandemic in 2009, or H5N1, the current flu killing birds around the world. The new mutations have happened in a group of H3N2 influenzas.
So what can we do about it?
The vaccine will still trigger the body to produce antibodies that can recognize the influenza virus. The biggest benefits are anticipated to be in lessening the severity of the disease rather than stopping you getting ill or slowing the spread of the virus. And the flu vaccine protects against multiple strains of flu, each of which has the potential to cause their own waves of infections.
Meanwhile, doctors have been sent advice reminding them that early antiviral treatment reduces the risk of complications from flu. Japan is also going through an early flu season and has closed schools to help contain outbreaks. These are not Covid-style lockdowns, but short-term measures the country uses to disrupt the spread of the virus. Nobody knows for certain what will happen in the coming months.