What we know about the HMPV virus spreading in China

Reports of rising respiratory virus cases in China have raised grim echoes of the start of the Covid-19 pandemic nearly five years ago.

But despite the superficial similarities, this situation is very different, and much less worrisome, medical experts say.

The Chinese cases are reported to be infections with the human pneumonia virus, known to doctors as HMPV. Here’s what we know so far:

What is HMPV?

It is one of several pathogens that spread around the world every year, causing respiratory diseases. HMPV is common — so common that most people will become infected while they are still children and may have several infections in their lifetime. In countries with months of cold weather, HMPV can have an annual season, much like influenza, while in places closer to the equator it spreads at lower levels throughout the year.

HMPV is similar to a virus known in the United States — respiratory syncytial virus, or RSV. It causes symptoms very similar to those associated with influenza and Covid, including cough, fever, nasal congestion and wheezing.

Most HMPV infections are mild and resemble bouts of the common cold. But severe cases can lead to bronchitis or pneumonia, especially among infants, the elderly, and people with weakened immune systems. Patients with pre-existing lung disease, such as asthma, chronic obstructive pulmonary disease, or emphysema, are at greater risk of serious outcomes.

In high-income countries, the virus is rarely fatal; In low-income countries, with weak health systems and poor surveillance, deaths are more common.

How long has this virus been around?

The virus was identified in 2001, but researchers say it has been spreading among humans for a long time At least 60 years old. Although it’s not new, it doesn’t have the name flu, Covid or even RSV, said Dr. Lee Howard, an associate professor of pediatric infectious diseases at Vanderbilt University Medical Center.

One reason is that it is rarely discussed by name, except when people are hospitalized with a confirmed case of it.

“It’s really difficult to differentiate clinical features from other viral diseases, and we don’t routinely test for HMPV the way we test for coronavirus, influenza, or respiratory syncytial virus,” Dr. Howard said. “So most infections go unrecognized and are linked to anything related to the respiratory system.”

How does a person become infected with HMPV?

The virus spreads primarily through droplets or aerosols from a cough or sneeze, through direct contact with an infected person or through exposure to contaminated surfaces – in the same way people get the common cold, flu and Covid.

Is there a vaccine? Or a cure?

There is no vaccine against HMPV. But there is a vaccine for RSV, and research is underway to find a vaccine that can protect against both viruses with a single injection, because they are similar. There is no antiviral treatment specifically for HMPV; Treatment focuses on managing symptoms.

What does China say about it?

Chinese authorities acknowledged that HMPV cases are increasing, but stressed that the virus is a known entity and does not constitute a major concern. The coronavirus that causes COVID-19 was a new pathogen, so people’s immune systems had not built defenses against it.

At a press conference held by the Chinese Center for Disease Control and Prevention on December 27, Can Biao, director of the Center’s Institute of Infectious Diseases, said: He said HMPV cases are on the rise among children aged 14 years or younger. He said the increase was particularly noticeable in northern China. He added that influenza cases also increased.

He added that cases may rise during the Lunar New Year holiday, at the end of January, when many people travel and gather in large groups.

But overall, Mr. Kan said, “Judging by the current situation, the scale and severity of the outbreak of respiratory infectious diseases this year will be lower than last year.”

Official Chinese data show that HMPV cases have been on the rise since mid-December, in both outpatient and emergency cases. According to Xinhua News Agencygovernment news agency. The outlet said some parents and social media users were unaware of the virus and were seeking advice online; She urged calm and normal precautions such as washing hands frequently and avoiding crowded places.

In a Routine press conference on FridayA Foreign Office spokesman confirmed that cases of influenza and other respiratory viruses routinely increase at this time of year, but they “appear to be less serious and spreading on a smaller scale compared to the previous year.”

Chinese officials said last week that would happen Establishment of a surveillance system for pneumonia of unknown origin. China Central Broadcasting Corporation (CCTV) reported that the law will include procedures for laboratories to report cases and for disease control and prevention agencies to verify and deal with them.

How was the audience reaction in China?

Online, amid comments from people saying they had never heard of HMPV and expressing concern that it was a new pathogen, state media sought to reassure people, warning them against taking antiviral drugs blindly.

Some users made jokes saying they could finally use the masks they had been stockpiling during the coronavirus pandemic. Many commentators discussed a general rise in the disease, and not just HMPV: The question “Why does the flu hurt so much” was trending on Weibo, a social media platform, on Monday.

What does the World Health Organization say?

The World Health Organization did not express concern. Dr. Margaret Harris, spokeswoman for the organization, cited weekly reports from Chinese authorities that showed an expected rise in cases.

“As expected at this time of year, which is winter in the Northern Hemisphere, there is a monthly increase in cases of acute respiratory infections, including seasonal influenza, respiratory syncytial virus, and human pneumonia,” she said via email.

Should I be worried?

Reports from China recall those dating back to the confusing early days of the Covid pandemic, and the World Health Organization is still urging China to share more information about the origins of this outbreak, five years on.

But the current situation is different in key respects. Covid was a previously unknown virus that jumped to humans from animals. HMPV has been well studied, and there is widespread capacity to test for it. There is widespread population-level immunity to this virus globally; There was nothing for Covid. A severe HMPV season can strain hospital capacity – especially children’s wards – but does not overwhelm medical centres.

However, it is also important that China shares its data on this outbreak in a timely manner, said Dr Sanjaya Senanayake, an infectious disease specialist and associate professor of medicine at the Australian National University. “This includes epidemiological data about who gets infected. We will also need genomic data to confirm that HMPV is the cause, and that there are no significant mutations of concern.

Vivian Wang He contributed reporting from Beijing.