News reports and social media posts are warning of a new outbreak of a little-known virus called human metapneumovirus (HMPV) in China, but authorities have yet to confirm this.

Instead, official reports from the Chinese Center for Disease Control and Prevention suggest that the number of several flu-like illnesses is increasing in China, according to data through the last week of 2024.

This data suggests that the flu is leading the outbreak: 30.2 percent of tests came back positive – an increase of 6.2 percent from the previous week – and 17.7 percent of people were hospitalized with a serious respiratory illness were tested positive for it.

However, the same data set shows that HMPV rates are higher than other flu-like illnesses – such as COVID-19, rhinovirus and adenovirus – with 6.2 percent of positive tests for respiratory illnesses and 5.4 percent of hospitalizations for respiratory illnesses connected in China.

What is HMPV?

Human metapneumovirus (HMPV) is a virus that can cause a flu-like illness in people of all ages, although some people are more at risk, including young children, older adults and people with weakened immune systems.

The virus was only discovered in 2001, but belongs to the same family as respiratory syncytial virus (RSV), another flu-like virus.

The increased use of testing for certain viruses in people with flu-like symptoms has led to increased awareness of HMPV as a significant cause of respiratory illness.

How does HMPV spread?

Like other similar viruses, HMPV usually spreads from person to person through droplets from coughs and sneezes, through human contact such as hugging or kissing, and by touching surfaces and objects contaminated with the virus and then the mouth, nose or eyes.

In the United States, HMPV circulates seasonally along with influenza and similar illnesses and is most active in late winter and spring.

The U.S. Centers for Disease Control and Prevention (CDC) recommends several ways for Americans to protect themselves from the virus: washing hands frequently with soap and water, avoiding touching the face with unwashed hands, and close contact with sick people .

People with flu-like symptoms are advised to cover their mouths when coughing or sneezing, wash their hands frequently with soap and water, avoid sharing cups and cutlery with others, avoid kissing others, and stay home to recover.

⚠️BREAKING:

China 🇨🇳 declares state of emergency as epidemic hits hospitals and crematoriums.

Several viruses, including influenza A, HMPV, Mycoplasma pneumoniae and COVID-19, are spreading rapidly across China. pic.twitter.com/GRV3XYgrYX

— SARS CoV 2 (COVID-19) (@COVID19_disease) January 1, 2025

What are the symptoms of HMPV?

HMPV symptoms are similar to those of other flu-like illnesses, including cough, fever, and a stuffy or runny nose.

In some cases, sick people may experience shortness of breath, which can lead to bronchitis – an inflammation of the airways of the lungs – or pneumonia, an inflammation of the lungs themselves.

The duration of the illness depends on the severity of the sufferer’s symptoms, but is generally comparable to the flu.

Could this lead to another pandemic?

Because HMPV is a relatively recently recognized virus, there is neither a specific treatment nor a vaccine for it.

People with HMPV are advised to treat the virus like the flu and stay home while the body fights the infection.

There is currently insufficient information from reliable sources about the scale and severity of a possible HMPV outbreak in China to accurately predict the risk of a pandemic.

However, because it is a virus that is already circulating among the population in China, the United States and elsewhere, there is greater herd immunity against it than against a novel virus like COVID-19 at the start of the pandemic.

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