HMPV: What You Need to Know About the New Virus in China

Reports from news outlets and social media have raised alarms about a potential outbreak of a little-known virus, human metapneumovirus (HMPV), in China. However, health authorities have yet to confirm the situation. According to official data from the Chinese Center for Disease Control and Prevention (CDC), flu-like illnesses have been on the rise in China, based on reports up until the final week of 2024.

The data points to influenza as the primary driver of the surge, with 30.2% of tests coming back positive for flu—an increase of 6.2 percentage points from the previous week. Additionally, 17.7% of patients hospitalized for severe respiratory conditions tested positive for influenza.

However, the same data reveals that HMPV cases have outpaced other flu-like illnesses, such as COVID-19, rhinovirus, and adenovirus, accounting for 6.2% of positive respiratory tests and 5.4% of hospitalizations for respiratory illnesses in the country.

What Is HMPV?

Human metapneumovirus (HMPV) is a virus that causes flu-like symptoms in individuals of all ages, though children, the elderly, and those with weakened immune systems are more vulnerable. Discovered only in 2001, HMPV belongs to the same virus family as respiratory syncytial virus (RSV), another common cause of respiratory illness.

With the increased use of diagnostic tests to identify specific viruses in people with flu-like symptoms, HMPV has become more widely recognized as a leading cause of respiratory infections.

How Is HMPV Spread?

HMPV spreads in a similar manner to other respiratory viruses, primarily through droplets from coughing or sneezing, direct physical contact like hugging or kissing, and by touching contaminated surfaces and then touching the face—mouth, nose, or eyes.

In the U.S., HMPV circulates seasonally, usually alongside the flu and similar viruses, and is most active during the late winter and spring months. The U.S. Centers for Disease Control and Prevention (CDC) suggests several precautionary measures to reduce the spread of the virus, including frequent handwashing, avoiding face-touching with unwashed hands, and steering clear of close contact with sick individuals.

Those showing flu-like symptoms should cover their mouth when coughing or sneezing, wash hands often, refrain from sharing eating utensils or drinks, avoid kissing others, and stay home to recover.

What Are the Symptoms of HMPV?

Symptoms of HMPV resemble those of other common respiratory viruses and include coughing, fever, and a runny or congested nose. In some cases, individuals may experience difficulty breathing, which can lead to more severe conditions such as bronchitis (inflammation of the airways) or pneumonia (lung inflammation).

The duration of illness varies depending on the severity of symptoms, but it typically lasts about as long as the flu.

Could This Lead to Another Pandemic?

As a virus that was identified relatively recently, HMPV has no specific treatment or vaccine. Individuals infected with the virus are generally advised to treat it like the flu, focusing on rest and self-care while the immune system fights off the infection.

At present, there is insufficient reliable data to determine the extent of a potential HMPV outbreak in China or assess its potential to cause a global pandemic. However, since HMPV already circulates in various countries, including China and the U.S., there is likely a higher level of herd immunity compared to a completely new virus, such as COVID-19 at the start of the pandemic.