What is the HMPV virus in China? The human metapneumovirus and its symptoms, explained.
The human metapneumovirus, also known as HMPV, is reportedly surging in China, raising questions about what the illness is and if it's a concern to those in the U.S.
Officials in India have also confirmed cases of HMPV. Seven people there have contracted the virus as of Tuesday, according to the Indian Council of Medical Research.
Chinese health officials have not confirmed that HMPV is what is driving hospitalizations in the country, and recent reports from China's Center for Disease Control and Prevention indicate the increase may actually be due to influenza A. But with less public knowledge around HMPV in the U.S., worries of a potential new pandemic have risen — though experts say there isn't need for alarm.
"The concern for a pandemic can be put at rest," Dr. Carla Garcia Carreno, Children's Medical Center Plano director of infection prevention and control, told CBS News, adding not only is the virus fairly stable, it's also not a novel virus like COVID-19 was. "This has been circulating for a while, so people have some immunity against this human metapneumovirus."
What is HMPV?
HMPV is a virus that can cause upper and lower respiratory disease in people of all ages. Young children, older adults and people with weakened immune systems are the most at risk for serious illness from the virus.
The length of illness varies depending on the severity on an individual'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
- Nasal congestion
- Shortness of breath
"Clinical symptoms of HMPV infection may progress to bronchitis or pneumonia and are similar to other viruses that cause upper and lower respiratory infections," the CDC's 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 RSV, according to the CDC.
It may have been circulating even earlier — for decades or over a century, Garcia Carreno said.
In the U.S., HMPV typically circulates beginning in the winter and lasts until or through spring, the CDC says, and can circulate simultaneously with RSV and the flu during the respiratory virus season.
Is HMPV worse than COVID?
Experts say the HMPV outbreak in China is not of major concern — it is neither a new, mystery illness 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 tests of respiratory viruses. In comparison, the flu accounted for nearly 19% and COVID just over 7% for the same week.
For a disease to be considered widespread locally, it needs to be above 10% of positive results for two weeks. At 1.9%, Garcia Carreno said it's not close to the numbers of flu, 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 tract infection like pneumonia," the clinic's website adds.
HMPV transmission and prevention
HMPV is transmitted through direct contact with someone who has it or from touching things contaminated with the virus.
"Unfortunately, compared to flu, RSV and COVID, we don't have a vaccine for human metapneumovirus, so we don't have that advantage of priming over or boosting our immune system to fight these viruses," said Garcia Carreno. "But still, everything else that we learned for COVID can apply to human metapneumovirus."
To prevent illness, take similar steps to preventing other respiratory viruses, meaning wash hands with soap and water and avoid close contact with sick people.
"If somebody's sick, try to avoid crowding so they don't expose everybody, especially the vulnerable people," said Garcia Carreno. "If that person is sick and can not avoid going to a place where other people are, then try to use a mask, use cough and sneezing etiquette and good hand washing."