What is the new super flu strain affecting the UK?

The current severe flu strain in the UK is H3N2, which has undergone mutations making it 'hotter' and 'nastier'.

Why does the UK flu strain cause vomiting bile?

Vomiting yellow bile is a symptom of the H3N2 flu due to stomach lining inflammation when vomiting on an empty stomach, often because of a reduced appetite.

Should I get the flu jab amid the H3N2 outbreak in the UK?

Yes, health officials urge eligible individuals to get vaccinated to reduce the risk of severe illness and hospitalisation, even if protection against the new strain isn't complete.

Home / Health / UK Flu Strain Causes Vomiting Bile

UK Flu Strain Causes Vomiting Bile

3 Jan

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Summary

A super flu strain, H3N2, is causing more severe symptoms like vomiting bile.
Mutations have made the H3N2 variant 'hotter' and 'nastier,' increasing vulnerability.
Vomiting yellow bile occurs on an empty stomach due to stomach lining inflammation.

A severe strain of influenza, identified as H3N2, is currently circulating in the UK, leading to more intense symptoms, notably the vomiting of yellow bile. Experts suggest that genetic mutations have rendered this H3N2 variant more aggressive, making people more susceptible to infection and its associated discomforts.

This particular strain is characterized by a swift onset of symptoms, including significant body aches and sudden fatigue. Vomiting yellow bile, a recurring patient report, is attributed by virologists to the virus's impact on appetite, leading to vomiting on an empty stomach. This symptom, while sometimes confused with 'stomach flu,' is a direct result of stomach lining inflammation.

UK Health Security Agency data from November 2025 indicated a surge in flu cases, with H3N2 dominating. Hospital admissions were notably higher than typically expected for that time of year. Health officials are strongly encouraging eligible populations, including the elderly and vulnerable groups, to receive flu and COVID-19 vaccinations to prevent severe outcomes, even though the current vaccine may not offer full protection against the mutated strain.