In recent weeks, scenes of hospitals in China full of masked people have been circulating on social media, raising concerns about a new pandemic.
Beijing has since acknowledged an increase in cases of the flu-like human metapneumovirus (HMPV), particularly among children, and attributed it to a seasonal increase.
But HMPV is not like Covid-19, public health experts said, noting that the virus has been around for decades, and almost every child is infected by their fifth birthday.
However, it can cause more serious illness in some very young children and people with weakened immune systems. Here’s what you need to know.
What is HMPV and how does it spread?
HMPV is a virus that will lead to a mild upper respiratory infection in most people – virtually indistinguishable from the flu.
First identified in the Netherlands in 2001, the virus spreads through direct contact between people or when someone touches surfaces infected with it.
Symptoms for most people include cough, fever and nasal congestion.
The very young, including children under two, are most susceptible to the virus, along with those with weakened immune systems, including the elderly and those with advanced cancer, said Hsu Li Yang, an infectious disease doctor in Singapore.
If infected, a “small but significant proportion” of the immunocompromised will develop more severe disease involving the lungs, with wheezing, shortness of breath and symptoms of croup.
“Many will need hospital care, with a lower risk of death from infection,” said Dr. Hsu.
Why is the number of cases increasing in China?
Like many respiratory infections, HMPV is most active during late winter and spring — some experts say this is because the virus survives better in the cold and spreads more easily from one person to another because people stay indoors more often.
In northern China, the current spike in HMPV coincides with cold temperatures expected to last until March.
In fact, many countries in the northern hemisphere, including but not limited to China, are experiencing an increased prevalence of HMPV, said Jacqueline Stephens, an epidemiologist at Flinders University in Australia.
“While this is concerning, the increased prevalence is likely a normal seasonal increase seen in winter,” she said.
Data from health authorities in the US and the UK show that those countries have also seen an increase in HMPV cases since last October.
Is HMPV like Covid-19? How worried should we be?
Fears of a Covid-19 pandemic are overblown, experts said, noting that pandemics are usually caused by new pathogens, which is not the case with HMPV.
HMPV has a global presence and has existed for decades. This means that people around the world have “some degree of pre-existing immunity due to previous exposure,” said Dr. Hsu.
“Almost every child will have at least one HMPV infection by their fifth birthday, and we can expect to have multiple re-infections throughout their lives,” says Paul Hunter, professor of medicine at the University of East Anglia in England.
“So, all in all, I don’t think there are any signs of a more serious global problem right now.”
Still, Dr. Hsu advises standard general precautions such as wearing a mask in crowded places, avoiding crowds where possible if there is a higher risk of more serious illness from respiratory viral infections, practicing good hand hygiene and getting a flu shot.
