The flu-like viral illness has surged in China in recent months, particularly infecting children, raising concerns about its potential spread.
Cases of human metapneumovirus (HMPV) have also been reported from India amid seasonal winter patterns of increased respiratory disease. Chinese health officials are piloting a tracking system, while authorities in India are advising people not to panic.
Here’s what you need to know about the virus, which is transmitted like other respiratory illnesses like the flu and COVID-19.
What is HMPV?
Human metapneumovirus is a respiratory virus that causes flu-like or cold-like symptoms.
The virus peak during late winter and spring, according to the US Centers for Disease Control and Prevention.
The disease was first identified in 2001 in the Netherlands very often infect almost every child up to the age of five.
HMPV is tested by taking a sample of mucus from the nose or throat using a swab. Similar to COVID, the sample is analyzed in a laboratory, often with RT-PCR tests. Other methods, such as antigen tests, can also identify the virus.
How is HMPV transmitted?
HMPV enters the body through the nose, mouth or eyes, usually after inhaling droplets from an infected person when they cough, sneeze or breathe, or after touching contaminated surfaces.
These modes of transmission are similar to those of colds, flu and other respiratory viruses.
What does HMPV do to the body?
After entering the body, the virus binds to the epithelial cells that line the respiratory tract, which includes the airways and lungs.
These epithelial cells form a protective barrier in the airways, helping to protect the respiratory system while clearing mucus, dust and other debris.
Once inside the cells, the virus replicates, producing more viral particles. These newly formed viruses infect neighboring cells, spreading through the respiratory epithelium.
The body’s immune system detects the infection and initiates an inflammatory response to fight the virus. Although necessary to clear the virus, this reaction contributes to symptoms of infection, such as nasal congestion and coughing.
Which countries have seen an increase in HMPV cases?
In northern China, cases of HMPV are increasing among children 14 and younger, according to Kan Biao, director of the Chinese Institute of Infectious Diseases.
The sudden jump coincides with the cold winter months, during which respiratory infections are more common.
In response to the surge in cases, China’s National Administration for Disease Control and Prevention said it was implementing a pilot surveillance system for pneumonia of unknown origin.
Countries such as India and the United Kingdom have also reported a seasonal increase in HMPV from the end of 2024.
India has reported seven confirmed cases of HMPV in several states, including Karnataka, Gujarat, Maharashtra and Tamil Nadu.
The Indian government advised states to step up surveillance of respiratory diseases and advised the public not to panic and to follow standard precautions such as washing hands regularly and avoiding close contact with others.
IN UKbetween December 23 and 29 last year, about 4.5 percent of laboratory-tested samples were positive for HMPV, which is a slight increase compared to the previous week. In comparison, 29.5 percent were positive for the flu, and 2.5 percent for COVID-19.
Precise global data on the virus is rare because surveillance and reporting of the virus is not as robust or routine as influenza or COVID-19.
Is it contagious or deadly? Who is more at risk?
HMPV spreads easily but is usually not fatal in healthy people.
Most people have mild symptoms similar to a common cold or flu and fully recover within seven to ten days.
Exact death rates have been difficult to measure due to limited data and overlap with other respiratory diseases. However, in low-resource settings where access to health care is limited, HMPV-related deaths were relatively more common.
In addition, in some people the virus can lead to more severe respiratory complications, such as bronchitis, an inflammation of the airways leading to the lungs, or pneumonia, an infection of the lung tissue. This includes high-risk groups such as infants, older adults, and immunocompromised individuals.
Infants, for example, have smaller and more delicate airways, which can easily become inflamed or blocked during respiratory infections. Moreover, their immune system and body are still developing, which makes it difficult to fight the virus.
Aging also reduces immune function, while underlying health conditions make it harder to deal with viruses.
What are the symptoms of HMPV infection?
These symptoms usually appear within three to six days of infection and often include:
- Cough
- Fever
- Nasal congestion
- Wheezing
- Loss of breath
- Sore throat
Vulnerable groups may experience more severe and long-lasting symptoms.
How can HMPV infection be treated?
There is no antiviral treatment or vaccine for HMPV alone.
Instead, treatment focuses on managing symptoms, such as using antipyretic medications, staying hydrated, and resting.
Severe cases, especially those involving pneumonia or significant respiratory distress, may require hospitalization and supportive care such as oxygen therapy.
