What is Human Metapneumovirus (hMPV)?
hMPV was first discovered in 2001 by scientists from the Netherlands in a group of children where tests for other known respiratory viruses were negative.
But it was probably around long before that. Testing of samples from the 1950s demonstrated antibodies against this virus, suggesting infections have been common for at least several decades. Studies since have found hMPV in almost all regions in the world.
Australian data prior to the COVID pandemic found hMPV to be the third most common virus detected in adults and children with respiratory infections. In adults, the two most common were influenza and RSV (respiratory syncytial virus), while in children they were RSV and parainfluenza.
What are the symptoms of hMPV?
For most people, hMPV will cause symptoms similar to a cold or the flu. In rare cases, hMPV can lead to severe infections.
In young children, hMPV most commonly causes infections of the upper respiratory tract, with symptoms including runny nose, sore throat, fever as well as ear infections. These symptoms usually resolve over a few days to a week in children and 1–2 weeks in adults.
How is hMPV transmitted?
It is presumed that hMPV is transmitted by contact with respiratory secretions either through the air or on contaminated surfaces. Therefore, personal hygiene measures and avoiding close contact with other people while unwell should reduce the risk of transmission.
Are there any vaccines or treatments?
There are no treatments that have been clearly demonstrated to be effective. But for severely unwell patients certain antivirals may offer some benefit.
It is hoped that similar products may be developed for hMPV, and Modern has recently started trials into a mRNA hMPV vaccine.
Why are we hearing so many reports of respiratory viruses now?
Since the COVID pandemic, the pattern of many respiratory infections has changed. For example, in Australia, influenza seasons have started earlier (peaking in June–July rather than August–September).
Many countries, including Australia, are reporting an increased number of cases of whooping cough (pertussis).
In China, there have been reports of increased cases of mycoplasma, a bacterial cause of pneumonia, as well as influenza and hMPV.
Conclusion
While hMPV can cause severe infections in some cases, it is not likely to cause the next pandemic. The generally mild nature of the illness, the widespread detection of antibodies reflecting broad population exposure and immunity, combined with a lack of any known major pandemics in the past due to hMPV, suggests there’s no cause for alarm.
FAQs
Q: What is hMPV?
A: hMPV is a respiratory virus that was first discovered in 2001.
Q: How is hMPV transmitted?
A: hMPV is transmitted by contact with respiratory secretions either through the air or on contaminated surfaces.
Q: What are the symptoms of hMPV?
A: For most people, hMPV will cause symptoms similar to a cold or the flu. In rare cases, hMPV can lead to severe infections.
Q: Are there any vaccines or treatments?
A: There are no treatments that have been clearly demonstrated to be effective. But for severely unwell patients certain antivirals may offer some benefit. A mRNA hMPV vaccine is currently in trials.
Q: Why are we hearing so many reports of respiratory viruses now?
A: Since the COVID pandemic, the pattern of many respiratory infections has changed. For example, influenza seasons have started earlier, and there have been reports of increased cases of whooping cough and mycoplasma.
