As new data suggests a rise in HMPV cases in the US, experts are calling for greater transparency from China regarding an influenza outbreak overwhelming its hospitals. China claims that respiratory illnesses are “less severe” and “smaller in scale” compared to 2024, attempting to downplay the viral images circulating on social media of crowded wards and waiting areas.
These images have sparked concerns that the spread of the relatively unknown human metapneumovirus (HMPV) in China may echo the early stages of the 2019 COVID outbreak, which was initially reported in the country. The symptoms of HMPV include cold-like signs such as headaches, chills, fatigue, and congestion.
Dr. Sanjaya Senanayake, an infectious diseases expert at the Australian National University, emphasized the importance of China sharing data about the outbreak in a timely manner. This includes information on who is being infected, along with genetic data to confirm HMPV as the culprit and determine whether any concerning mutations have emerged. Such data would also aid in the development of vaccines, Senanayake noted.
In the US, the number of HMPV cases has surged, with test positivity rates doubling from the beginning to the end of December. The CDC reported that fewer than 300 positive results were recorded during the final week of December. Although the CDC is “monitoring” the situation in China, it has stated that the current cases in the US “are not currently a cause for concern.”
Dr. Andrew Catchpole, chief scientific officer at infectious disease biotech company hVIVO, noted that HMPV typically peaks in winter in several countries. However, he observed that “rates of serious infection may be higher in China than what we would expect in a normal year.” According to the CDC’s National Respiratory and Enteric Virus Surveillance System (NREVSS), HMPV cases in the US have surpassed last year’s numbers. In the last week of December, the positivity rate stood at 1.9%, with 300 confirmed cases out of 13,800 tests.
