Since the end of summer, a new strain of influenza A has been circulating throughout the United Kingdom. And it is rather aggressive: in the hospital, cases are soaring and severe forms are multiplying. What are the particularities of this virus? Should we fear the arrival of this variant in our country? Dr. Gérald Kierzek, medical director of True Medical, answers us frankly.
A strain of flu that circulates very quickly
Across the Channel, the health authorities seem to have taken it by surprise. The flu started much earlier and much stronger this year, to the point where the epidemic threshold for the disease has already been exceeded. And the appearance of this new strain of influenza A, particularly virulent, is not for nothing.
“The currently circulating influenza A(H3N2) virus acquired seven new mutations over the summer, meaning it is quite different from the A(H3N2) strain included in this year’s vaccine.explains Dr Antonia Ho, clinical lecturer and infectious diseases specialist at the University of Glasgow. “This also means that the virus may have changed enough to escape immunity acquired from previous infections or vaccinations.”.
An ability “to multiply”, confirmed by Dr Gérald Kierzek.
“This new variant (subclade K of H3N2) – resulting from a mutation that took place last summer – shows an increased capacity to circumvent the usual immune defenses… and the vaccine. The situation is being monitored very closely, but, fortunately, there is no question here of a pandemic out of control”,
says Dr. Gérald Kierzek.
New variant: how to recognize it?
The symptoms of H3N2 remain relatively “classic”: high fever (often above 39°C), chills, body aches, headaches, intense fatigue, dry and sometimes painful cough. But this strain would also cause more severe forms in the elderly… while causing “prolonged fatigue“, assures the emergency doctor.
Experts also observe:
- A sudden onset of fever associated with overwhelming fatigue;
- More marked respiratory complications in vulnerable populations;
- Increased circulation of the strain among younger people (including adolescents) and seniors.
What steps if you catch it?
Certainly, the H3N2 strain is more aggressive, particularly in populations at risk (seniors), but is not classified as a pathogen at risk. So there is no need to panic if you contract it. On the other hand, some good reflexes must be adopted:
- Consult a healthcare professional promptly if symptoms worsen or persist for more than 10 days;
- Stay isolated and avoid contact with vulnerable people, particularly seniors and immunocompromised people;
- Apply barrier gestures: regular hand washing, wearing a mask if necessary, coughing into your elbow;
- Rest, hydrate, and monitor symptoms;
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Influenza vaccination: the seasonal vaccine remains partially effective and offers significant protection against severe forms, especially for children and adults at risk (70-75% effectiveness in children, 30-40% in adults).
The main risk in the coming weeks?
Even if it is difficult to predict the intensity of the flu epidemic, we can fear that mutations in this strain, if it becomes dominant in France, could be the cause of a large number of cases, because the vaccine used would then only offer partial protection.
Nevertheless, Dr Gérald Kierzek wants to be reassuring about the real risks.
“The main risk lies in the fact that the season is particularly severe for older people, with an early wave and possible increased complications. But at this stage, there is no threat of an uncontrollable pandemic, and vaccination remains the best weapon to limit the severity of infections, including other strains/variants. No maximum alert measure has been introduced, but vigilance is recommended for fragile people and their loved ones,” concludes Dr Gérald Kierzek.