Human Metapneumovirus

According to the US CDC, cases of human metapneumovirus – also known as hMPV – spiked this spring. In comparison to pre-pandemic figures, nearly 11% of tested specimens were positive for hMPV at its peak in mid-March – a number that is about 36% higher than the average pre-pandemic seasonal peak of 7% test positivity. This surge in cases has health professionals and researchers on keeping a close eye on the virus through continued surveillance and concerted research into this widespread respiratory pathogen.

What is hMPV?

First identified in the Netherlands in 2001, hMPV has since been recognized as a common and significant cause of respiratory illness. Belonging to the Pneumoviridae family and Metapneumovirus genus, hMPV is a negative-sense single-stranded RNA virus responsible for upper and lower respiratory tract infections.

The clinical manifestation of hMPV infection can range from mild to severe, with symptoms including cough, wheezing, difficulty in breathing, and fever. Severe cases can lead to bronchiolitis or pneumonia, particularly in infants, elderly individuals, and people with weakened immune systems. Most children are infected with hMPV before the age of five. While the infection can cause mild symptoms akin to the common cold in healthy adults, it can be severe and potentially life-threatening in the elderly and immunocompromised individuals. The virus primarily spreads from person-to-person through respiratory droplets, similar to other respiratory viruses such as influenza, RSV and COVID-19. It shows increased activity during the winter and early spring months in temperate climates, and can survive on surfaces for several hours, facilitating its spread, especially in crowded environments.

Diagnosing and Treating hMPV

Diagnosis of hMPV generally involves polymerase chain reaction (PCR) testing, which detects the presence of viral RNA in respiratory samples. There are currently no specific antiviral treatments for hMPV infection; however, management of the infection primarily involves supportive care, which may include hydration, fever management, and in severe cases, hospitalization for oxygen therapy or mechanical ventilation; while prevention measures focus on good hygiene practices, such as frequent hand washing, avoiding close contact with sick individuals, and regularly cleaning and disinfecting surfaces.