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

Chinese official reports indicate a surge in human metapneumovirus (HMPV) cases, sparking concerns and online speculation about a potential new pandemic similar to COVID-19. However, in short, this is not a major cause for excessive worry.

HMPV is a respiratory illness that causes cold-like symptoms, including a runny nose and cough, but can also develop into more serious conditions such as pneumonia. Unlike COVID-19, HMPV is not a new virus to humans, with the first human infection reported in the Netherlands in 2001. Since then, cases have also been reported in Australia, the UK, the US, and other parts of the world.

China has experienced a surge in HMPV cases during its winter season, with photos of crowded hospitals circulating on social media. Children have been particularly affected by this outbreak. Kan Biao, director of the National Institute for Communicable Disease Control and Prevention at the Chinese Center for Disease Control and Prevention, stated in a December 27 release that the incidence of HMPV is rising among children aged 14 and under in China, according to the China Daily. However, a surge in HMPV cases is not uncommon during China's flu season, and the China Daily also reported that this winter's flu season is less intense compared to the last peak season.

Young children, adults over 65, and people with weakened immune systems are more susceptible to developing more severe HMPV cases, including pneumonia, bronchitis, and asthma exacerbations. There is currently no vaccine or antiviral treatment for HMPV, but severe cases can be treated in hospitals. "Human metapneumovirus is quite common in Australia and has been around for a long time," Australian Health and Aged Care Minister Mark Butler said in a statement on Sunday. "We're obviously monitoring it, just as we monitor influenza, COVID, and respiratory syncytial virus (RSV)."

The COVID-19 pandemic was caused by an animal-borne disease that spilled over into the human population for the first time, while HMPV has been circulating in the global population for over 20 years. Therefore, there is a greater scientific understanding of this virus compared to COVID-19. "We're monitoring the situation in China," Butler said. "I've asked my department to keep me up to date. But this is quite a familiar thing for us." Measures to prevent the spread of HMPV are the same as those 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 sick people, wear a mask, and stay home when sick.