Britons who thought they had weathered the worst of the winter flu are finding themselves struck down again by a new wave of illness, with a so-called 'mystery bug' sweeping the nation as 2026 begins.
What Is The 'Mystery Virus'?
Pharmacist Ian Budd, speaking to the Mirror from Chemist4U, has clarified that the illness lining up with reports from clinicians and public health bodies is likely a strain of Adenovirus. This is not a new virus, but a common respiratory pathogen that appears to have spiked significantly, leading to a surge in GP visits.
Budd explained that, compared to a common cold, Adenovirus can be more likely to cause fever and conjunctivitis (pink eye), and its symptoms can last longer. The bug causes a runny nose, coughing, sneezing, and can also lead to stomach issues.
How Is The Adenovirus Spreading?
The virus spreads from person to person through several common routes, which explains its rapid circulation. Transmission occurs through close physical contact, airborne germs from coughs and sneezes, and touching contaminated surfaces before touching your face.
Significantly, the US Centers for Disease Control and Prevention (CDC) also notes that infection can occur via water, such as in poorly chlorinated swimming pools, though this is less common. Parents and carers are warned that the virus can also be caught from contact with an infected person's excrement, such as during nappy changes.
Why Is It Hitting After The Winter Flu?
Many are asking why this wave of illness has followed directly on the heels of the severe 'super flu'. According to Ian Budd, the festive period and flu outbreak led to more people congregating indoors in close proximity, facilitating the spread.
He also suggested that with COVID-19 restrictions lifted and fewer viruses circulating in recent years, community immunity may be lower, making people more susceptible. Furthermore, a person can continue 'shedding' the virus and infecting others long after their own symptoms have cleared, particularly posing a risk to those with weaker immune systems.
The main symptoms of Adenovirus include:
- Fever
- Sore throat
- Acute bronchitis or pneumonia
- Pink eye (conjunctivitis)
- Acute gastroenteritis (causing vomiting, nausea, diarrhoea, and stomach pain)
Less common symptoms can involve inflammation of the bladder and, very rarely, neurological disease affecting the brain and spinal cord.
