Human Metapneumovirus Cases Surge in China: Should We Be Concerned?

Can you tell me what human metapneumovirus is, why are there so many instances in China, and why should we be concerned?

Despite internet panic about a recent spike in HMPV cases in northern China, scientists have downplayed the likelihood of a new Covid-like epidemic.

People who are already at a higher risk of developing bronchitis or pneumonia, as well as those who are very young, very old, or have impaired immune systems, are more likely to get human metapneumovirus (HMPV), a respiratory illness that produces flu-like symptoms.

Initially detected in the Netherlands in 2001, the illness has been around since then and belongs to the same family as respiratory syncytial virus (RSV). Its occurrence is more often in the winter.

Why has HMPV made headlines?

Authorities in the north of China have reported an alarming increase in cases, especially among minors. The country’s center for disease control (CDC) has cautioned people to take measures with health and cleanliness, but has also pushed back from internet reports of swamped hospitals and worries of another Covid-like epidemic.

According to Mao Ning, a representative for China's foreign ministry, "Respiratory infections tend to peak during the winter season." This information was released on Friday.

It seems like the infections aren't as bad this year and are spreading on a lesser scale.

The apparent rise in cases is likely partially due to improved technologies more readily detecting and diagnosing HMPV, scientists told the Guardian.

Also, “I think we’re just more cautious of outbreaks now”, said Dr Jacqueline Stephens, a senior professor in public health at Flinders University in Australia. “Everyone is hypervigilant, and you hear this term human metapneumovirus and it sounds kind of scary.”

How dangerous is HMPV?

As Stephens pointed out, the symptoms of herpes simplex virus (HMPV) are quite similar to those of the common cold and influenza. It is not a notifiable illness like Covid-19 or influenza.

“There’s a range of others … Those are not notifiable since they are so prevalent and many of individuals acquire them. They make us feel bad for a few days but if we relax and recoup for a few days then we get better,” said Stephens.

Who is most at risk?

HMPV may develop to more severe infections such bronchitis and pneumonia among older adults, very young children, and persons who are immunocompromised.

“It certainly can and does cause severe disease, that’s why I think it’s important that people know it’s out there,” said said Prof Paul Griffin, head of infectious diseases at Mater Health Services in Brisbane.

“The challenge is at the moment there’s not much we can do except educate people [that] it’s around to reduce transmission. There’s no vaccination or antivirals, but there are several vaccines under development,” said Griffin.

How concerned should we be?

HMPV is unlike like Covid-19, in that it has been there for many decades and there is a degree of protection in the worldwide population from earlier infections, the specialists added. Covid-19 was a novel illness which had never infected humans before, fueling the pandemic-level spread.

“I don’t think we’re necessarily concerned about a pandemic with this virus, but the surge in cases and impact it’s having are significant,” said Griffin. “A good lesson can be taken [from the pandemic] to reduce the spread, particularly given we don’t have vaccines or antivirals for HMPV.”

What should we do about it?

“I’m certainly not suggesting we go back to the harsh restrictions of Covid, but staying home, practising good cough and sneeze etiquette, and hand hygiene are so important during the winter season.”

“For a number of years [during Covid] we were good at precautions for reducing the numbers, now we are doing less, and we’re seeing a rebound,” said Griffin.

Both experts also recommended individuals not to go to work when unwell, and Stephens suggested wearing a mask if you do have to go into the community, to avoid further infecting others, particularly those at greater risk.