Human metapneumovirus, a poorly understood virus, responsible for a spike in infections in the United States

The United States has just emerged from a spring marked by respiratory infections in toddlers and seniors due to human metapneumovirus, a virus poorly understood by the general public. Isolated only since 2001, scientists believe that it had already been circulating for more than 50 years without anyone noticing it. Thanks to improved screening techniques, it is now known to be an important cause of upper and lower respiratory tract infections in children – almost all children under 5 are infected with this virus – but also in children. adults.

A virus responsible for many respiratory infections in the spring

Human metapneumovirus is an RNA virus that belongs to the paramyxovirus family. It circulates seasonally with a peak of propagation at the end of winter. In the United States, the peak is between early March and mid-April, with more than 15% of screening tests for the human metapneumovirus positive for this 2023 season. It causes the classic symptoms of a respiratory infection: sneezing, coughing , difficulty breathing, fever. Symptoms in most cases mild, but which can degenerate into pneumonia in the most fragile. Young children, seniors, and immunocompromised people are most at risk of developing severe symptoms that require hospitalization.

According to one study, between 5-10% of hospitalizations for respiratory infection in adults over 50 are due to human metapneumovirus, slightly less than for influenza or respiratory syncytial virus (RSV). Without a vaccine to prevent infection, hygiene practices – such as washing hands and keeping a reasonable distance from a sick person – can break the transmission dynamics of the virus.