Cases of human metapneumovirus (hMPV) are rising in the UK, weeks after images of packed hospital waiting rooms in China sparked alarm on social media.

It was dubbed the “mystery virus” as experts debated the cause of intense pressure on the country’s healthcare system.

Now, the UK Health Security Agency’s latest weekly winter virus surveillance report found that hMPV cases were increasing and at a “medium” level.

Or more than 7,000 patient samples that were tested by medics for viruses, 4.9% were positive for hMPV, with the highest positivity among those aged 80 and over at 7.3%.

The NHS remains under intense pressure from winter virusses including flu, norovirus, Covid and RSV, with 96% of adult hospital beds across England occupied.

What is hMPV?

hMPV is one of the viruses that causes the common cold. It usually causes only mild illness but can be more severe in rare cases, particularly for people who are more vulnerable due to age or health conditions.

First identified in 2001, the disease belongs to the same family as respiratory syncytial virus (RSV).

It has been found around the world and spreads when particles move through the air from a sick person to someone else.

People who have weakened immune systems such as infants and older adults, and those with respiratory conditions like asthma may suffer worse symptoms.

What are the symptoms?

People infected with hMPV typically have cold and flu-like symptoms, including a cough, fever, sore throat or runny nose. Some may also suffer with body aches and headaches.

In more serious cases it can lead to pneumonia or inflammation of the airways in the lungs, known as bronchitis or bronchiolitis.

More severe symptoms include wheezing, difficulty breathing, chest pain, dizziness, severe fatigue, dehydration or persistent fever.

The World Health Organisation advises that people experiencing these more severe symptoms should seek medical advice.

How is it treated?

There is no approved anti-viral medicine or vaccine for hMPV. Most people can manage their symptoms with over-the-counter remedies that combat flu-like symptoms.

In the worst cases, patients may receive supportive care in hospital such as supplemental oxygen or mechanical ventilation.

Can it be prevented?

Measures such as wearing a face mask, improving ventilation and washing hands can reduce the risk of spreading infection.

Eating a balanced diet, exercising regularly, and sleeping properly can also generally help keep the immune system strong.