Is this the start of a new pandemic? As HMPV spreads as China, PAT HAGAN reveals all you need to know about the ‘mystery’ illness

The scenes are eerily familiar: Overcrowded hospitals in China are overrun by masked patients seeking medical attention as the infection sweeps through the population.

But this time it is not Covid-19 that is doing the damage. Instead, doctors are struggling to deal with high rates of illness caused by another organism known as human metapneumovirus, or HMPV.

The virus causes cold and flu-like symptoms, but can be dangerous for certain groups, especially children and the elderly.

And worryingly, other countries are also reporting a spike in cases – which have doubled in just a month in Britain.

So how worried should you be – and could this be the start of the next pandemic? Here’s everything you need to know…

What is HMPV?

HMPV belongs to the same family of infectious insects as respiratory syncytial virus (RSV), which is already a common source of pulmonary bronchiolitis in winter, causing around 30,000 children and 18,000 adults to be hospitalized in Britain each year.

Respiratory viruses peak in winter because we spend more time indoors and closer together, making it easier for insects to spread.

HMPV was first officially identified by a team of Dutch scientists in 2001, but evidence suggests it has been circulating for hundreds of years.

You may not have heard of it before, as it is just one of many viruses (at least 200 at last count) known to cause cold and flu symptoms in Britain every year.

In fact, it is estimated that almost every child in the country has had at least one HMPV infection by the time they reach their fifth birthday, which in most cases would have been just a sniffle.

Why are we only hearing about this now?

HMPV has hit the headlines due to a rise in cases in China, especially in children – with social media flooded with images of hospitals being overwhelmed.

Although it has not released official data, China says there has been a spike in HMPV cases in the north of the country, while India, Malaysia and Kazakhstan have also announced a rise.

How dangerous is it?

For most healthy adults, this is unlikely to cause serious problems. But in very young babies, as well as the elderly and anyone with a chronic illness, including leukemia or rheumatoid arthritis, HMPV can lead to worrying complications.

These include pneumonia and bronchiolitis (especially in babies), where the virus causes dangerous inflammation in the small airways. Bronchiolitis kills around 20 to 30 babies a year in Britain. And especially in the elderly, acute respiratory infections increase the risk of heart attacks and strokes.

A 2018 study by University College London suggested that viral infections could be responsible for almost one in 30 heart-related deaths among those over 75.

How do I know if I have it?

You wouldn’t do that – unless you were very sick and were tested for it. But in the vast majority of cases, the main symptoms are very similar to those of a cold: cough, stuffy or runny nose, sore throat and low-grade fever.

Like other viruses, these are caused by the body’s immune system trying to fight it. Some people may also experience nausea and vomiting, but in most cases this is very short-lived; symptoms often disappear within two to five days.

You probably wouldn’t be tested for the infection unless it caused complications that landed you in the hospital, where doctors may have to clarify what caused your symptoms.

If so, they may be able to do a rapid antigen test – like the DIY Covid tests used during the pandemic – which examines a nasal swab for the presence of the hMPV virus.

Or they can use a more sensitive and high-tech PCR test (again similar to that used for Covid) that looks for traces of genetic material from the virus in nasal swabs.

Are cases in China the start of a pandemic?

Experts have noted that although HMPV is usually detected in the winter period, the number of serious infections in China may be higher than would normally be expected.

But leading British experts say this outbreak is unlikely to be the start of a pandemic.

HMPV replicates slowly and mutates into new strains much more slowly than flu or Covid. Even if this HMPV outbreak is due to a new strain of the virus – for which there is no evidence yet – the expert consensus is that it is likely to be similar enough to other circulating strains and that our body’s defenses will already have some will have a degree of immunity to.

“Although HMPV mutates over time and new strains emerge, we do not believe it is a virus that has pandemic potential,” said Dr. Andrew Catchpole, Chief Scientific Officer at HVIVO, an independent research body based in Britain that helps in the development of vaccines. against infectious diseases.

Compare this virus to Covid-19 – this was a completely new pathogen. The human immune system was ill-equipped to deal with this until vaccines arrived.

Pandemics usually occur in two ways. Either a completely new pathogen enters the human population, or a new variant of an existing virus, formed by a combination of a human and animal version, forms a powerful new organism. Could this have happened? Dr. Catchpole adds: ‘There is no such animal reservoir of related viruses for HMPV.’

Will it overwhelm the NHS?

According to the UK Health Security Agency, HMPV is currently at what it describes as a ‘medium’ level of activity.

For example, in the week ending December 23, 2024, 4.53 percent of hospital patients in England who had undergone a PCR for the virus tested positive, up from 2.5 percent at the start of the month and five times the number that tested positive during the week ending December 23, 2024. summer.

That said, the numbers aren’t radically different from the same time last year. To put it in context, the number of people who tested positive for flu in the same week was over 14 percent, and for RSV it was 7.35 percent.

Paul Hunter, professor of medicine and expert in infectious diseases at the University of East Anglia, said it may be because improved testing methods are detecting more cases – rather than the number of infections actually increasing dramatically.

How does it spread?

In much the same way as other cold, flu or Covid viruses: it is largely airborne and moves from one person to another by inhaling infected droplets.

These penetrate deep into the lungs, where the virus hijacks healthy cells to use them as a reproduction factory and spread further.

But as with cold and flu viruses, HMPV can also be picked up by touching contaminated surfaces or through direct contact with an infected person, especially if they touch you in places where the virus can easily enter the body – such as around the mouth, nose or eyes. Symptoms appear within three to six days.

How can I avoid getting it?

The most effective defense is the same basic hygiene measures for any winter virus: washing hands with soap and warm water (to remove any virus particles lurking on your skin) and cleaning surfaces in the home regularly.

Some experts recommend avoiding high-contact surfaces, such as handrails and doorknobs, in crowded places – and wearing face masks in crowded environments.

How do I treat it?

In most cases, no treatment other than the usual over-the-counter remedies for cold and flu symptoms, such as paracetamol and ibuprofen, is required.

Is there a vaccine?

No, but there are several in development aimed at babies.