Human metapneumovirus (hMPV): symptoms, who is at risk and what helps

Human metapneumovirus is a single-stranded RNA virus that causes respiratory tract infections in children, adults and older people. A 2025 review in Cureus says it was identified in 2001 in the Netherlands, and that it is spread mainly by droplets or aerosols, or by direct contact with an infected person, with an incubation period of three to five days.

It is one of several viruses that circulate during winter, alongside the cold viruses, flu and RSV. Because many people have been infected by early childhood, the illness is often mild, but the virus can cause more serious illness in some groups. Reinfection through life is common because immunity is incomplete.

The review describes a spectrum from fever, cough and runny nose to wheezing, croup, bronchiolitis and pneumonia. Less common features include conjunctivitis, otitis media, diarrhoea, rash and seizures. It notes the clinical picture is indistinguishable from RSV in features such as fever, cough, breathlessness and low oxygen levels.

For adults, the NHS descriptions of a cold and flu give a useful guide to what a mild respiratory virus feels like. A cold comes on gradually over 2 to 3 days with a blocked or runny nose, sneezing, sore throat and cough, and you should begin to feel better in about 1 to 2 weeks. Flu appears quickly, within a few hours, with a high temperature, aching body and exhaustion.

In babies and young children the same infection can cause bronchiolitis. The NHS describes the early symptoms as cold-like, followed by a cough, faster breathing, difficulty feeding, noisy breathing and irritability, with symptoms usually worst between days 3 and 5 and the cough usually improving within 3 weeks.

The review says hMPV can cause respiratory infection in immunocompromised people, older adults and people with conditions such as COPD, asthma or cancer, as well as in infants and children. It adds that older adults are at increased risk because of a diminishing immune response.

For children, the NHS identifies babies under 6 months, babies and children born prematurely and those with a weakened immune system or long-term lung or heart conditions as having a higher risk of becoming seriously ill with bronchiolitis, which is usually caused by RSV but can have other viral causes.

The review says the recommended laboratory test is reverse transcription polymerase chain reaction (RT-PCR) on a respiratory sample, since the virus is hard to grow in culture. In practice, most mild infections are not tested for a specific virus, and a clinician bases decisions on symptoms and how unwell the person is.

There is no specific antiviral treatment in the sources used here. The review describes supportive care, including oxygen supplementation, fever and anti-inflammatory medicines and fluids. The NHS advice for bronchiolitis is children’s paracetamol or ibuprofen for distress, keeping the child upright when awake, checking regularly including at night, encouraging fluids, not smoking around the child and not giving aspirin to anyone under 16.

For a child, the NHS says to call 999 if there is difficulty breathing with grunting, tummy sucking under the ribs or fast breathing, pauses in breathing, blue or grey skin, tongue or lips, or the child is floppy and will not wake or stay awake. It says to ask for an urgent GP appointment or call 111 if a cold is getting worse, feeding is much reduced, there are signs of dehydration such as a dry nappy for 12 hours, a very high or low temperature, or you are worried.

For adults with a respiratory virus, the NHS says to ask for an urgent GP appointment or call 111 if you are 65 or over, pregnant, have a long-term condition or weakened immune system, feel very unwell, feel short of breath or symptoms do not improve after 7 days with flu, and to call 999 for sudden chest pain, severe difficulty breathing or coughing up blood.

Hand washing, covering coughs and sneezes, cleaning shared surfaces and keeping newborn babies away from people with colds or flu all help reduce spread, according to the NHS.