Respiratory viruses like RSV, influenza and COVID-19 ran rampant during the past winter. But just as they were winding down, a little-known virus that poses a grave threat to children and older adults is picking up pace.

Human Metapneumovirus (HMPV) is a respiratory virus that was first identified in 2020. It has the capability to infect people across age groups, with a higher prevalence among young children, older adults and those with weakened immune systems. Classified under the Pneumoviridae family, HMPV is responsible for causing a range of respiratory symptoms.

HMPV cases spiked this spring, filling hospitals and medical facilities. Approximately 11% of tested specimens were positive for HMPV, which is approximately 36% higher than the average test positivity rate during the pre-pandemic seasonal peak of 7%.

Common symptoms

  • Cough
  • Runny nose
  • Nasal congestion
  • Sore throat
  • Fever

In more severe cases, patients may experience wheezing, shortness of breath and asthma flare-ups. Secondary respiratory infections such as bronchiolitis, bronchitis or pneumonia may also occur, requiring additional medical care.

The situation can escalate into a severe condition as a significant number of HMPV cases go unnoticed due to people not recognizing their symptoms. Insufficient testing and the lack of availability of vaccination further contribute to the situation, CNN reported.

HMPV can be transmitted to humans through respiratory secretions from coughing and sneezing, as well as close personal contact such as touching or shaking hands.

It is the second most prevalent cause of respiratory infections in children after RSV (respiratory syncytial virus). In fact, data from a four-year period revealed that HMPV resulted in a similar number of hospitalizations among both children and older adults compared to RSV.

The virus closely resembles the avian metapneumovirus, which infects birds. Scientists believe the virus likely jumped from birds to humans and evolved from there.

"Basically, they could only identify a virus in people about half the time. And so the question was, 'OK, what about that other half?'" Dr. John Williams, a pediatrician at the University of Pittsburgh who has spent his career researching vaccines and treatments for HMPV, told CNN.

COVID-19 lockdown
A survey conducted in nearly 50 countries around the world showed that many employees would go to work even when sick or showing flu-like symptoms, particularly those in healthcare settings. Pixabay