CASES of the human metapneumovirus, also known as HMPV, are reportedly surging in northern China, prompting fears of another Covid-like pandemic.
Chinese authorities first issued warnings about HMPV in 2023, but reports indicate cases may be increasing again during China’s winter season.
In recent weeks, scenes of hospitals in China overrun with masked people have made their rounds on social media.
The country’s centre for disease control (CDC) has warned people to take precautions with health and hygiene, but has also pushed back against online claims of overwhelmed hospitals and fears of another pandemic.
Health experts have also assured HMPV isn’t like Covid, noting the virus has been around for decades.
Prof Sir Andrew Pollard, Director of the Oxford Vaccine Group in the Department of Paediatrics at the University of Oxford University, said: “Human metapneumovirus virus is a common respiratory virus which was first identified almost a quarter of a century ago by Dutch scientists.”
The virus is known to cause a respiratory illness in babies and in the elderly which can result in hospitalisation.
But in most other age groups it simply causes the symptoms of a cold, said Prof Pollard.
He continued: “It is one of the many viruses which circulate in the winter and add to the winter pressures on the NHS.
“The reports of respiratory infections in China in the past few days appear to be attributed to both influenza and this human meta pneumovirus, which is rather similar to the situation in the UK this week. “
According to Prof John Tregoning, Professor in Vaccine Immunology, Imperial College London, it has very similar symptoms (in children at least) to RSV (respiratory syncytial virus).
RSV is a common cause of coughs and colds.
Infections usually get better by themselves, but as Prof Pollard suggested, can sometimes be serious for babies and older adults.
Prof Tregoning added: “As with all respiratory viruses, there will be a range of symptoms and severity.”
HMPV presents similar symptoms to RSV – an RSV infection usually starts within a few days of getting infected.
The NHS says most people only get cold-like symptoms, such as:
Babies may also be irritable and feed less than usual.
If a more serious infection occurs (such as pneumonia or bronchiolitis) it may also cause:
Prof Paul Hunter, Professor in Medicine, UEA, said symptoms usually recover by themselves within two to five days.
He advised: “Just occasionally it can cause more severe disease in the elderly, the very young (under two years of age) or medically vulnerable.
“It is one of the leading viral causes of respiratory infections in children under five years.”
Professor Jill Carr, a Virologist in the College of Medicine and Public Health at Flinders University in Adelaide, Australia, said HMPV is very different to the Covid-19 pandemic.
She said: “This is very different to the Covid-19 pandemic, where the virus was completely new in humans and arose from a spill-over from animals and spread to pandemic levels because there was no prior exposures or protective immunity in the community.
“The scientific community also has some understanding of the genetic diversity and epidemiology of HPMV, the kind of impact the virus has on the lungs and established laboratory testing methods – again, very different to the COVID-19 pandemic, where a new lung disease was seen, there was little information on how the virus may vary and spread and we had no initial diagnostic tests.
“HMPV can certainly make people very sick, and high case numbers are a threat to effective hospital services, but the current situation in China with high HMPV cases is very different to the threats initially posed by SARS-CoV-2 resulting in the Covid-19 pandemic.
“It will be very interesting to learn more about the current circulating HMPV strains, and to see if the simple things we did during the Covid-19 pandemic, such as physical distancing, masking measures and use of rapid antigen testing, can reduce HMPV spread.”
Distinguished Professor Vasso Apostolopoulos is a Professor of Immunology in the School of Health and Biomedical Sciences at RMIT University in Melbourne, Australia, suggested what may be to blame for the outbreak in China.
She said: “Contributing factors to the outbreak may be due to increased vulnerability to co-infections (such as RSV and influenza), and seasonal/environmental conditions like cold weather, which facilitate viral transmission.
“While this outbreak isn’t linked to a more dangerous strain, the growing number of cases and pressure on healthcare systems in densely populated regions like China highlight the need for enhanced surveillance and prevention strategies.
“Ensuring effective monitoring and timely responses will be key to mitigating the public health risks of this outbreak.”
While there is currently no vaccine and treatment, if necessary, supports symptoms, Prof Hunter said there’s no sign of the HMPV cases in China becoming a global issue.
He said: “One of the issues involved in these types of infection is that they are being diagnosed more frequently as we move to molecular diagnostic panels, so it is not always easy to know whether year on year increases are due to actual increases or just because we are diagnosing a greater proportion of infections.
“In England we have seen a fairly marked increase in respiratory viruses in recent weeks.
“So far the peak percentage positivity is a little over what it was this time last year so no major difference to usual, unless infections positivity rates continue to increase in coming weeks.
“So overall, I don’t think there is currently any signs of a more serious global issue.”
