What is the HMPV virus in China? The human metapneumovirus and its symptoms, explained.

The human metapneumovirusalso known as HMPV, is reportedly on the rise in China, raising questions about what the disease is and whether it is a concern for those in the U.S.

Chinese health authorities have not confirmed that HMPV is driving hospitalizations in the country, and recent reports from China Center for Disease Control and Prevention indicate that the increase may actually be due to influenza A. But with less public knowledge about HMPV in the U.S., concerns about a potential new pandemic have risen — though experts say there’s no need for alarm.

“The worry of a pandemic can be put to rest,” Dr. Carla García Carreno, Children’s Medical Center Plano director of infection prevention and control told CBS News, adding that not only is the virus fairly stable, it’s not a new virus like COVID-19 was. “This has been circulating for a while, so people have some immunity to this human metapneumovirus.”

What is HMPV?

HMPV is a virus that can cause upper and lower respiratory diseases in people of all ages. Young children, older adults and people with weakened immune systems are most at risk of serious illness from the virus.

The length of illness varies depending on the severity of a person’s case, but is similar to other respiratory infections caused by viruses, according to the Centers for Disease Control and Prevention.

HMPV symptoms

According to the CDC, symptoms commonly associated with HMPV include:

• Cough
• Fever
• Stuffy nose
• Shortness of breath

“Clinical symptoms of HMPV infection can progress to bronchitis or pneumonia and are similar to other viruses that cause upper and lower respiratory tract infections,” the CDC website notes.

Is HMPV a new virus?

HMPV is not new. It was first discovered in 2001 and is part of the Pneumoviridae family along with respiratory syncytial virus, or RSVAccording to the CDC.

It may have circulated even earlier — for decades or over a century, Garcia Carreno said.

In the United States, HMPV typically circulates beginning in winter and lasts until or through spring, the CDC says, and can circulate concurrently with RSV and influenza during respiratory virus season.

Is HMPV worse than COVID?

Experts say the HMPV outbreak in China is not cause for major concern — it is neither a new, mysterious disease nor responsible for as many cases as COVID or other infections even this season. According to the latest CDC data, HMPV accounts for less than 2% of weekly positive respiratory virus tests. In comparison, influenza made up almost 19% and COVID just over 7% in the same week.

For a disease to be considered widespread locally, it must be over 10% of positive results for two weeks. At 1.9%, Garcia Carreno said it’s not close to the rates of influenza, COVID and RSV.

Researchers estimate that about 10% to 12% of respiratory illnesses in children are caused by HMPV, according to the Cleveland Clinic.

“Most cases are mild, but about 5% to 16% of children will develop a lower respiratory infection such as pneumonia,” the clinic’s website adds.

HMPV transmission and prevention

HMPV is transmitted through direct contact with someone who has it or by touching things contaminated with the virus.

“Unfortunately, compared to influenza, RSV and COVID, we don’t have a vaccine against human metapneumovirus, so we don’t have the advantage of priming or boosting our immune system to fight these viruses,” Garcia Carreno said. “But still, everything else we’ve learned about COVID can apply to methane.”

To prevent illness, take similar steps to prevent other respiratory viruses, which means washing your hands with soap and water and avoiding close contact with sick people.

“If someone is sick, try to avoid crowding so they don’t expose everyone, especially the vulnerable people,” Garcia Carreno said. “If that person is sick and can’t avoid going somewhere where other people are, try to wear a mask, use cough and sneeze etiquette and good hand washing.”