What is the HMPV Virus That is Raising Concerns in China?

The buzz is growing about an increase of respiratory virus cases in China, but Adriana Weinberg, MD, professor of infectious diseases in the Departments of pediatrics and medicine at the University of Colorado School of Medicine, says the news is no cause for alarm.

Unlike the COVID-19 virus in 2020, Weinberg says, the current virus reportedly on the rise in China is one that has been around for decades, commonly circulates during respiratory virus season — along with influenza and respiratory syncytial virus (RSV) — and is well known to health care professionals.

Known as human metapneumovirus (HMPV), the virus is reported to be on the rise in China. A spokesperson for the World Health Organization recently told ABC News that “there has been a recent rise in acute respiratory infections,” but that “the overall scale and intensity of respiratory infectious diseases in China this year are lower than last year.”

In a separate statement Monday, the Centers for Disease Control and Prevention in the U.S. said it is “monitoring reports of increased disease" in China. The reports are "not currently a cause for concern in the U.S.,” the agency told ABC.

We asked Weinberg for more information on HMPV and how it’s diagnosed and treated.

What is the history of HMPV, and whom does it primarily affect?

HMPV has been around about as long as other respiratory viruses, but it was identified only 14 years ago. It's related to RSV and influenza. It's not particularly pathogenic, but it does cause an influenza-like disease, primarily in children. Children younger than 5 years of age and particularly in the first year of life may develop severe disease that requires hospitalization. Other groups that have a higher likelihood of developing severe disease with HMPV are immunocompromised individuals and older adults.

To our knowledge, HMPV does not mutate, unlike SARS/COVID or influenza, which mutate frequently. That’s why people may develop repeated episodes of disease with these viruses and why vaccines for SARS and influenza have to be periodically updated. HMPV resembles RSV; its antigenic characteristics are very stable, which is why HMPV disease is not common in older children and young adults.

Are you seeing HMPV cases rise in Colorado this winter, along with flu and RSV?

We don't have an increase in the incidence of HMPV at this point. We see mostly influenza and RSV, in terms of respiratory infections that require hospitalization or come to medical attention.

When people are hospitalized for HMPV, how is it treated?

There is no specific treatment right now. There are no antiviral drugs active against HMPV, so the treatment is symptomatic. Depending on the severity of the disease, people may require oxygen supplementation, hydration, and advanced forms of respiratory support.

There are several pharmaceutical companies that are currently working on an HMPV vaccine, and other companies are developing antivirals, so eventually we may have both a vaccine and antiviral treatment for HMPV.

Is HMPV any more contagious than flu and RSV?

No. There is nothing unique about how contagious it is.

What are the common symptoms of HMPV?

HPMV disease typically starts like a cold, including runny nose, congestion, sore throat, coughing and low-grade fever. If it progresses to the lungs, people develop more severe coughing, shortness of breath, and fever.

How is it diagnosed?

It's diagnosed by a PCR test of respiratory secretions through a nasal swab, similar to the test for COVID-19. HMPV is not part of the most commonly used respiratory PCR panel, which currently includes SARS/COVID, influenza, and RSV. HMPV is part of an extended panel that's most commonly used for hospitalized and immunocompromised people.

How does HMPV spread?

Through respiratory transmission, so droplets in the air from people coughing and sneezing, similar to how influenza spreads.

What are the best ways to prevent HMPV?

The same thing we recommend for other respiratory viruses — masks, handwashing, and good hygiene.