hMPV is likely one of the viruses making us sick this winter. Here’s what to know about human metapneumovirus

As winter settles over Australia, it’s not just the drop in temperature we notice – there’s also a sharp rise in respiratory illnesses. Most of us are familiar with the usual winter players such as COVID, influenza and RSV (respiratory syncytial virus), which often dominate news headlines and public health messaging.

But scientists are now paying closer attention to another virus that’s been spreading somewhat under the radar: human metapneumovirus (hMPV).

Although it’s not new, hMPV is now being recognised as a significant contributor to seasonal respiratory infections, especially among young children, older people, and people with weaker immune systems.

So what do you need to know about this winter lurgy?

What does a hMPV infection look like?

hMPV is a close relative of RSV, and can cause infections in the upper or lower respiratory tracts.

Like other respiratory viruses, hMPV infection causes symptoms such as cough, fever, sore throat and nasal congestion. While most people experience relatively mild illness and recover in about a week, hMPV can lead to serious illness – such as bronchiolitis or pneumonia – in babies, older adults, and people with weakened immune systems.

hMPV spreads much like the flu or SARS-CoV-2 (the virus that causes COVID) – through tiny droplets from coughs and sneezes, and potentially by touching surfaces where the virus has landed and then touching your mouth, nose, or eyes.

Most people will catch it at some point in their lives, commonly more than once. While an infection confers some immunity, this wanes over time.

hMPV generally follows a seasonal pattern, tending to peak in winter and spring.

hMPV around the world

By the end of 2024, China saw a surprising spike in cases of hMPV – enough to catch the attention of public health experts. While there were some suggestions hospitals were becoming overwhelmed, exact numbers were not clear.

The World Health Organization subsequently issued a statement in January indicating this rise in hMPV infections in China aligned with expected seasonal trends.

Other countries, such as the United States, have also noted increases in hMPV infections since the COVID pandemic. Realising hMPV might be playing a more significant role in seasonal illness than we’d previously thought, and with improvements in diagnostic technology, global health agencies have ramped up their monitoring.

Read more: hMPV may be spreading in China. Here's what to know about this virus – and why it's not cause for alarm

In Australia, comprehensive national data on hMPV is limited because hMPV is not one of the viruses with mandatory reporting. In other words, if a patient is found to have hMPV (through a PCR swab sent to a pathology lab) there’s no requirement for the doctor or the pathology lab to make a public health report of a positive result, as they would with another illness such as influenza, RSV or measles.

However, selected medical clinics voluntarily participate in systematic data collection on specific health conditions, which give us an idea of the proportion of people of people who may be infected (though not the absolute numbers).

The Australian Sentinel Practice Research Network (ASPREN) is a national surveillance system funded by the federal department of health. In 2024, up to December 15, based on ASPREN data, 7.8% of patients presenting with fever and cough symptoms tested positive for hMPV.

This year, to June 1, ASPREN data shows us hMPV has made up 4.2% of infections among people with flu-like illness, behind RSV (7.7%), COVID (10.9%), influenza (19%) and rhinovirus (a virus which causes the common cold, 46.1%).

What about vaccines and treatments?

hMPV is likely to be part of the array of respiratory viruses circulating in Australia this winter. If you have a cold or flu-like illness and have done one of those at-home rapid tests for COVID, flu and RSV but came up all negative, it’s possible hMPV is the culprit.

There’s currently no specific treatment or vaccine for hMPV. Most cases are mild and can be managed at home with rest and symptom relief such as taking medication (paracetamol or ibuprofen) for pain and fever. But more serious infections may require hospital care.

If your baby or young child has a respiratory infection and is having trouble breathing, you should take them to the emergency department.

Researchers and companies such as Moderna, Pfizer and Vicebio are actively working on vaccines for hMPV, however they’re not yet available.

The best way to protect yourself and others against hMPV and other respiratory viruses is through simple hygiene practices. These include washing your hands often, covering coughs and sneezes, staying home if you’re sick, cleaning shared surfaces regularly, and considering wearing a mask in crowded indoor spaces during virus season.