Data from Australia indicates that the H3N2 flu strain has caused the country’s worst influenza season on record, a trend that health experts warn could be mirrored in Britain as winter approaches. In Japan, the same strain has led to widespread school closures as infections reach epidemic levels, with thousands of people requiring hospital treatment.
Health officials in Britain have already warned that flu has arrived around a month earlier than usual, raising concerns that too few eligible people are taking up the offer of a free NHS flu vaccine. The latest figures reveal that two in five care home residents are still unvaccinated, prompting renewed calls for vulnerable groups to come forward for their jabs. The Royal College of Paediatrics and Child Health (RCPCH) has warned H3N2 “can kill” and has called on parents to give their children the flu vaccine nasal spray.
Dr Helen Stewart, RCPCH officer for health improvement, said: “This year it’s looking like a particularly bad season – rates of flu are much higher at this point than they were at this point last year.
“And we know that there’s been some changes to the flu virus circulating, which means that people might be more susceptible to infection.
“Unfortunately, it’s not just the elderly and people with chronic, long-term health conditions that get flu, it can make previously very fit and well children very, very poorly.
“Thousands of kids need to go to hospital because they have flu every year.”
She added: “Unfortunately, it can kill.
“Children do die every year from flu, so it is definitely not just a bad cold.
“The main complications that we see are pneumonia, so a severe chest infection needing breathing support, and that can tip over into sepsis and very extreme cases.
“I’ve seen some very, very sick children going to intensive care with flu.”
H3N2 has mutated to better escape immunity from previous vaccines. This is because it has mutated to be particularly aggressive.
On the surface of the virus particle, there are two protein spikes called hemagglutinin (orange in the main image) and neuraminidase (green). Haemagglutinin plays a role in the attachment of the virus to human respiratory cells. Neuraminidase plays a role in releasing newly formed virus particles from an infected cell.
As all flu virus strains, the newly mutated H3N2 can cause a sudden onset of the following symptoms:
- Fever/chills
- Cough (often dry)
- Sore throat
- Runny or stuffy nose
- Body and muscle aches
- Headache
- Fatigue/weakness
However, for H3N2, there is a tendency for the fever to be worse. Patients often experience a higher average body temperature and a greater likelihood of a high fever – above 38°C – compared to strains like H1N1.
The most effective way to prevent the flu is by receiving the annual flu vaccine. Additional precautions include practising good hygiene, such as washing your hands regularly, avoiding touching your face, and covering your mouth and nose when coughing or sneezing. Other measures that can help reduce the risk of infection include regularly cleaning frequently touched surfaces and steering clear of crowded places whenever possible.
It is estimated that deaths from flu in England stood at 7,757 last winter compared to 3,555 the year before. Child deaths involving flu also increased from 34 to 53.