What do you know about human coronavirus cases in China

In recent weeks, scenes of hospitals in China crowded with masked people have spread on social media, raising fears of another pandemic.

Beijing has since acknowledged a rise in human influenza-like pneumonia virus (HMPV) cases, especially among children, and attributed this to a seasonal rise.

But public health experts said HMPV is not the same as Covid-19, noting that the virus has been around for decades, with nearly every child infected by their fifth birthday.

However, in some very young children and people with weakened immune systems, it can cause more serious illness. Here's what you need to know.

HMPV is a virus that causes a mild upper respiratory infection — practically indistinguishable from influenza — for most people.

The virus was first identified in the Netherlands in 2001, and is spread through direct contact between people or when someone touches surfaces contaminated with it.

Symptoms in most people include cough, fever, and nasal congestion.

Hsu Li Yang, an infectious diseases doctor in Singapore, says the very young, including children under 2, are most vulnerable to the virus, along with those with weakened immune systems, including the elderly and those with advanced cancer. .

If infected, a “small but significant proportion” among immunocompromised people will develop more serious illness in which the lungs are affected, with wheezing, shortness of breath and symptoms of croup.

“Many will require hospital care, with a smaller percentage at risk of death from infection,” Dr. Hsu said.

Like many respiratory infections, HMPV is most active in late winter and spring — and some experts say this is because the viruses survive better in the cold and spread more easily from person to person as people stay home more.

In northern China, the current rise in HMPV coincides with low temperatures that are expected to continue until March.

Many countries in the Northern Hemisphere, including but not limited to China, are actually seeing an increasing prevalence of HMPV, said Jacqueline Stevens, an epidemiologist at Flinders University in Australia.

“While this is concerning, the increased prevalence is likely to be the normal seasonal increase we see in the winter,” she said.

Data released by health authorities in the US and the UK show that these countries have also seen a sharp rise in HMPV cases since October last year.

Experts said that fears of a coronavirus-style pandemic are exaggerated, noting that pandemics are usually caused by new pathogens, which is not the case for HMPV.

HMPV exists globally and has been around for decades. This means people around the world have “some degree of existing immunity due to previous exposure,” Dr. Hsu said.

“Almost every child will have at least one HMPV infection by their fifth birthday, and we can expect to have multiple infections throughout life,” says Paul Hunter, a professor of medicine at the University of East Anglia in England.

“In general, I don't think there are currently any signs of a more serious global problem,” he added.

However, Dr. Hsu advises taking standard general precautions such as wearing a mask in crowded places, avoiding crowds where possible if a person is at higher risk for more serious illness due to respiratory virus infections, practicing good hand hygiene, and getting a flu shot.