What do we know about HMPV, a virus spreading in China

Reports of a surge in respiratory virus cases in China have brought back dim echoes of the beginning of the Covid-19 pandemic almost exactly five years ago.

However, despite the apparent similarities, the situation is completely different and much less disturbing, medical experts say.

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

What is HMPV?

It is one of several pathogens that circulate around the world every year and cause respiratory diseases. HMPV is common – so common that most people will become infected during childhood and may experience several infections during their lifetime. In countries that experience chilly weather months, HMPV may have an annual season, much like influenza, while in places closer to the equator it circulates at lower levels year-round.

HMPV is similar to a virus better known in the United States, respiratory syncytial virus (RSV). It causes symptoms similar to those associated with flu and Covid, including cough, fever, nasal congestion and wheezing.

Most HMPV infections are subtle and resemble attacks of the common chilly. However, severe cases may cause bronchitis or pneumonia, especially in infants, the elderly and immunocompromised people. Patients with pre-existing lung diseases such as asthma, chronic obstructive pulmonary disease or emphysema are at greater risk of developing sedate complications.

In higher-income countries, the virus is rarely fatal; in lower-income countries with faint health systems and surveillance, deaths are more common.

How long has this virus existed?

The virus was identified in 2001, but scientists say it has been circulating among humans for a long time at least 60 years old. While it’s not fresh, it doesn’t have a name recognized as flu, Covid or even RSV, said Dr. Leigh Howard, an associate professor of pediatric infectious diseases at Vanderbilt University Medical Center.

One reason is that the disease is rarely mentioned by name, except when people are hospitalized with a confirmed case.

“The clinical features are really hard to distinguish from other viral diseases, and we don’t routinely test for HMPV like we do for Covid, flu or RSV,” Dr. Howard said. “So most infections go undiagnosed and are attributed to what’s happening with the respiratory system.”

How does a person become infected with HMPV?

The virus spreads mainly through droplets or aerosols produced by coughing or sneezing, through direct contact with an infected person, or through contact with contaminated surfaces – essentially the same way people contract colds, flu and Covid-19.

Is there a vaccine? Or treatment?

There is no vaccine against HMPV. However, there is a vaccine for RSV and research is ongoing to find a vaccine that will protect against both viruses in one shot because they are similar. There is no antiviral treatment specifically for HMPV; treatment focuses on managing symptoms.

What does China say about this?

Chinese authorities admitted that the number of HMPV cases was increasing, but emphasized that the virus was a known disease and did not pose a sedate problem. The coronavirus causing Covid-19 was a fresh pathogen, so the human immune system did not build a defense against it.

At a press conference organized by the China Center for Disease Control and Prevention on December 27, Kan Biao, director of the center’s Institute of Infectious Diseases, he said that HMPV cases are increasing among children aged 14 and younger. The raise was particularly noticeable in northern China, he added. He added that the number of flu cases has also increased.

He added that cases could spike during the Lunar Novel Year holiday, in overdue January, when many people travel and gather in vast groups.

But overall, Kan said, “judging by the current situation, the scale and intensity of the spread of respiratory infectious diseases this year will be smaller than last year.”

Official Chinese data shows that HMPV cases have been increasing since mid-December, both in outpatient and emergency cases, according to Xinhuastate news agency. According to the website, some parents and social media users were not familiar with the virus and looked for advice on the Internet. urged people to remain tranquil and take common precautions, such as washing hands frequently and avoiding crowded places.

In routine press conference on FridayA spokesman for the Ministry of Foreign Affairs reiterated that cases of influenza and other respiratory viruses regularly raise at this time of year, but “they appear to be less sedate and are spreading on a smaller scale compared to last year.”

Last week, Chinese officials said yes establish a monitoring system for pneumonia of unknown origin. It will include procedures to enable laboratories to report cases and disease control and prevention agencies to verify and deal with them, state broadcaster CCTV reported.

What was the public reaction in China?

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

Some users joked that they would finally be able to apply up the masks they had collected during the coronavirus pandemic. Many commentators discussed the overall raise in cases, not just HMPV: “Why does the flu hurt so much” was trending on the social media platform Weibo on Monday.

What does the World Health Organization say about this?

WHO did not express concern. The organization’s spokeswoman, Dr. Margaret Harris, cited weekly reports from Chinese authorities that showed a predictable raise in cases.

“As expected for this time of year, winter in the Northern Hemisphere, there is a month-over-month raise in the number of acute respiratory infections, including seasonal influenza, RSV and human metapneumovirus,” she said by email.

On Tuesday, the organization issued a statement saying that “WHO is in contact with Chinese health officials and has not received any reports of unusual outbreak patterns.” He added: “Chinese authorities report that the healthcare system is not overwhelmed and no emergency declarations or responses have been issued.”

Should I be worried?

Reports from China are reminiscent of those in the early, confusing days of the Covid pandemic, and the WHO continues to insist that China release more information about the origins of the outbreak, five years later.

However, the current situation is different in key respects. Covid was a virus that passed to humans from animals and was previously unknown. HMPV is well studied and testing is widespread. There is widespread population immunity to this virus around the world; there was none, for Covid. A severe HMPV season may strain hospital capacity – especially pediatric units – but does not overload medical centers.

“However, it is also essential for China to share data on this epidemic in a timely manner,” said Dr. Sanjaya Senanayake, an infectious diseases specialist and associate professor of medicine at the Australian National University. “This includes epidemiological data on who gets infected. We will also need genomic data to confirm that HMPV is the culprit and that there are no significant mutations of concern.”

Vivian Wang reported from Beijing.