Here’s What to Know About Human Metapneumovirus

Reports of human metapneumovirus (HMPV), a common respiratory illness that causes flu- and cold-like symptoms, are growing across the Northern Hemisphere, including in China, though neither the World Health Organization (WHO) nor the CDC have expressed alarm at this time.

“Recently, there has been interest in HMPV cases in China including suggestions of hospitals being overwhelmed,” the WHO wrote in a press release. While acute respiratory infections, including seasonal influenza, rhinovirus, respiratory syncytial virus (RSV), and HMPV have increased, especially in northern provinces of China, “the observed increase in respiratory pathogen detections is within the range expected for this time of year during the Northern Hemisphere winter.”

Furthermore, “Chinese authorities report that the health care system is not overwhelmed and there have been no emergency declarations or responses triggered,” the agency added.

While HMPV infections can lead to hospitalization in some cases, most involve mild upper respiratory symptoms and most people recover after a few days.

Meanwhile, the CDC said in a statement that it is “aware of reported increases of HMPV in China and is in regular contact with international partners and monitoring reports of increased disease. These reports are not currently a cause for concern in the U.S.”

Ericka Hayes, MD, of the Children’s Hospital of Philadelphia, told MedPage Today that HMPV is well-known to medicine. “We know how it behaves,” she said, adding it’s likely that cases will increase in February and March.

“That is exactly how the viral season for [HMPV] goes and so I would not be concerned,” Hayes said, adding that it’s good to practice the usual infection prevention strategies of washing hands, staying home when sick, and masking.

Tina Tan, MD, president of the Infectious Diseases Society of America and a professor at Northwestern University’s Feinberg School of Medicine in Chicago, also told MedPage Today that cases of HMPV occur every year and won’t develop into a “pandemic virus.”

Spread of Infection, Tips for Prevention

HMPV spreads in the same way as most other viruses, from an infected person or a surface.

“So you can get it from infected secretions, from someone who’s coughing and sneezing,” Tan said, or from shaking hands or touching a person who’s been coughing or sneezing.

Much like other viruses, it lives on objects and surfaces that have been touched by an infected person. “Then someone else touches it, and basically then they touch their mouth, their eyes, their nose, and they infect themselves that way,” Tan explained. “So it’s very much like other viral infections and other respiratory diseases, where you want to encourage your patients to wash their hands often with soap and water … not just hand sanitizer.”

A person with the virus remains contagious for about 2 weeks, Tan noted. However, “if you are sick, and you’re still symptomatic, you really shouldn’t be sending someone to school or going to work, unless you want to wear a mask all the time.”

Most Vulnerable Populations

HMPV causes upper and lower respiratory infections in people of all ages, Tan said. Symptoms include fever, runny nose, cough, and nasal congestion.

“It’s very difficult to distinguish it from other respiratory viruses,” she noted.

Those at risk of developing more serious illness include children younger than 6 months, older adults, people with weakened immune systems, or anyone who is immunocompromised for any reason.

Young children can develop bronchiolitis, and older adults can develop bronchitis or pneumonia, Tan said, adding that in the worst cases, people can develop severe disease and would require hospitalization.

Hayes noted that some people “can sometimes even have the infection be complicated with a secondary bacterial infection. So, the virus sets you up to get a bacterial pneumonia … and patients can end up on oxygen. They can even end up on a ventilator, [and] in very severe cases, there can be fatalities.” However, these numbers are “nowhere near” those of influenza, she said.

Testing and Treatment Options

Places that typically have respiratory panels to test for HMPV include “minute clinics,” urgent care clinics, and emergency departments. The average physician’s office, on the other hand, typically won’t test for HMPV, Tan said.

Co-infection is also possible, she said, including with norovirus, RSV, flu, and COVID. “It’s not uncommon that someone comes to the hospital because they have all these symptoms, and you test them, and they come up positive for two, three viruses.”

“This is also another reason why people should get vaccinated against those viruses that we have vaccines for,” Tan explained, noting that there’s no antiviral treatment and no vaccine to prevent HMPV, so care is supportive.

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