What is human metapneumovirus and should we be worried about surging cases in China?

Chinese official reports of a surge in human metapneumovirus (HMPV) cases have sparked concern and online speculation about a potential new pandemic akin to COVID-19. However, in short, this is not a cause for high alarm.

HMPV is a respiratory illness that causes cold-like symptoms, including a runny nose and cough, but can also develop into more serious conditions like pneumonia. Unlike the novel coronavirus, HMPV is not a new virus to humans, with the first human infection reported in the Netherlands in 2001. Cases have since been reported in Australia, the UK, the US, and other parts of the world.

A surge in HMPV cases in China during the winter has led to social media circulation of photos of overcrowded hospitals. Children have been particularly affected by this outbreak. Kan Biao, director of the Institute for Infectious Disease Prevention and Control at the Chinese Center for Disease Control and Prevention, stated in a December 27 release, as reported by the China Daily, that the incidence of HMPV is increasing among children aged 14 and under in China. However, it is not uncommon for HMPV cases to surge during the flu season in China. The China Daily also reported that this winter’s flu season is less intense compared to the last peak season.

Young children, adults over the age of 65, and people with compromised immune systems are more likely to develop more serious HMPV cases, including illnesses such as pneumonia, bronchitis, and asthma exacerbations. Currently, there is no vaccine or antiviral treatment for HMPV, but severe cases can be treated in hospitals. Australian Minister for Health and Aged Care, Mark Butler, said in a statement on Sunday: “Human metapneumovirus is quite common in Australia, and has been for a very long time.” He also said: “We monitor it in the same way we monitor flu, COVID and respiratory syncytial virus.”

The COVID-19 pandemic resulted from the first spillover of an animal-borne disease into the human population, while HMPV has been circulating in the global population for over 20 years. Consequently, there is a deeper scientific understanding of this virus compared to what was known about the novel coronavirus. “We are monitoring the situation in China,” Butler said, “and I have asked my department to keep me updated. But this is something that is quite familiar to us.” Measures to prevent the spread of HMPV are the same as for other respiratory illnesses like COVID-19: wash hands with soap and water for at least 20 seconds, avoid touching eyes, nose and mouth with unwashed hands, avoid close contact with people who are unwell, wear a mask, and stay home when sick.