Recent reports from Chinese health officials indicate a rise in cases of human metapneumovirus (HMPV), prompting increased attention from global health agencies. While there is no evidence to suggest that a new or unusual respiratory illness has emerged, the World Health Organization (WHO) has acknowledged an uptick in acute respiratory infections in China. However, they emphasized that the overall scale and intensity of respiratory diseases in China this year remain lower than in previous years.
The Centers for Disease Control and Prevention (CDC) in the United States is also closely monitoring the situation. Although the rising number of cases in China is not yet a cause for concern in the U.S., health experts are keeping a watchful eye on this development. In fact, HMPV has been circulating steadily in the U.S. since November 2024, with around 1.94% of weekly tests positive for the virus as of late December 2024. In comparison, flu and COVID-19 remain more prevalent during this respiratory season.
First discovered in 2001, HMPV belongs to the Pneumoviridae family, which also includes respiratory syncytial virus (RSV). The virus primarily causes upper and lower respiratory illness, affecting people of all ages. Although it was once less recognized, advancements in diagnostic tools have increased awareness of HMPV in recent years, making it more detectable in hospitals, emergency rooms, and even doctor’s offices. This increased diagnostic capability has helped medical professionals identify and understand the virus better.
HMPV is considered a significant player in the annual respiratory virus season, which sees a rise in cases of influenza, RSV, and COVID-19, as well. Dr. William Schaffner, a professor of preventive medicine at Vanderbilt University Medical Center, explained that the winter season, with its indoor gatherings and travel, creates ideal conditions for the transmission of respiratory viruses like HMPV.
The incubation period for HMPV typically ranges from three to six days. Common symptoms include cough, nasal congestion, fever, and shortness of breath, which are similar to those caused by other respiratory viruses. However, as Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, pointed out, HMPV symptoms can be indistinguishable from those of other respiratory infections unless a patient is severely ill.
Young children and older adults, particularly those aged 65 and above, are at higher risk for complications such as bronchitis or pneumonia. Though the virus can affect anyone, these age groups should be vigilant, especially during the peak of respiratory virus season.
Like most respiratory viruses, HMPV spreads through respiratory droplets from coughing and sneezing, as well as through close personal contact and touching surfaces contaminated with the virus. This makes HMPV particularly contagious in crowded settings, such as homes, schools, and offices. In the U.S., HMPV cases typically rise during the winter months and taper off in the spring.
Most people are exposed to HMPV by the age of five, and while reinfection is possible, subsequent infections tend to cause milder symptoms. However, individuals who are immunocompromised or elderly may experience more severe symptoms, even with reinfection.
There is no specific antiviral treatment for HMPV. Supportive care is the primary approach to managing symptoms. This may include using bronchodilators to relieve wheezing, providing fluids for dehydration, and reducing fever with appropriate medications. In some cases, antibiotics may be required if bacterial co-infections are present.
Since no vaccine currently exists for HMPV, prevention hinges on basic hygiene practices, such as frequent handwashing, covering the mouth and nose when coughing or sneezing, and staying home when ill. Those who are at higher risk, such as older adults or those with weakened immune systems, should consider wearing masks in crowded spaces and practicing social distancing when necessary.
Additionally, getting vaccinated against other respiratory viruses, such as the flu, RSV, and COVID-19, can help reduce the risk of co-infection, which can make illnesses more severe. As Dr. Chin-Hong emphasized, minimizing the likelihood of co-infection is crucial, as the combination of HMPV and other respiratory infections can exacerbate symptoms and lead to more serious health outcomes.
While the recent rise in HMPV cases in China has caught global attention, experts assure that there is no immediate cause for alarm. However, as respiratory viruses continue to circulate globally, it’s important to stay informed about symptoms, preventive measures, and available treatments. With ongoing vigilance and appropriate health measures, the impact of HMPV and other seasonal viruses can be minimized, helping to keep communities safe during this respiratory virus season.
