What is human metapneumovirus, the infection that has peaked in the United States – breaking latest news

Il metapneumovirus umano (HMPV), discovered in 2001 in the Netherlands, an RNA virus that belongs to the family of paramyxovirus, viruses known to cause a variety of common infections. Investigations at the time revealed that the new pathogen, which caused severe unexplained respiratory infections in children, was closely related to the avian metapneumovirus, which infects birds. The new virus was therefore named human metapneumovirus. Scientists believe it probably is passed from birds to humans and which circulated for at least half a century before being discovered.

Other known paramyxoviruses are parainfluenza, respiratory syncytial virus (RSV), measles and mumps
. In most people, this virus causes just a simple cold. HMPV is the second most common cause of respiratory infections in children after RSV.

Why is the virus on the rise?

As with other respiratory diseases, cases of human metapneumovirus are on the rise, as reported by i Centres for Disease Control and Prevention which recorded unusual peaks in the United States. In mid-March in the US, almost 11% of the samples tested were HMPV positive, a number more than 36% higher than the average seasonal peak of the pre-Covid pandemic period. Experts speculate that the rise of a number of viruses, including RSV, may be a consequence of lockdown and the excessive use of masks which prevented the immune system from having contact with the usual viruses and then better manage future exposures. After years of social distancing children have less immunity capable of repelling multiple viruses simultaneously. Generally children are exposed to metapneumovirus by 5 years of age.

What are the symptoms of HPMV?

The virus, which usually appears in winter and spring, most commonly affects the upper respiratory tract, causing nasal congestion, coughing and shortness of breath, wheezing and difficulty breathing, as well as fever. The infection typically lasts three to seven days.

When does it get dangerous?

Human metapneumovirus is usually mild, but can have more serious consequences for young children, the elderly, and people with weakened immune systems. In some cases, it can progress to the lower respiratory tract, leading to more serious disease such as bronchiolitis
, which causes swelling, irritation and a buildup of mucus in the lungs or pneumonia. Depending on the severity, the virus typically lasts the same amount of time as other viruses, anywhere from three to seven days.

How is it transmitted?

Human metapneumovirus is spread in a similar way to other viruses: through airborne particles produced by coughing or sneezing, through physical contact with a person who has the virus, or by handling contaminated objects and then touching the eyes, mouth, or nose . The virus can spread even when people are asymptomatic, just like Sars-CoV-2. According to a study published in Jama asymptomatic human metapneumovirus infections account for at least 38% of infections.

How widespread?

A 2020 study on Lancet Global Health estimated that among children under the age of 5 there were more than 14 million HMPV infections in 2018, more than 600,000 hospitalizations and more than 16,000 deaths. infection generates weak or incomplete immune protection, and humans are reinfected for life.

Is there a vaccine?

There is no vaccine for human metapneumovirus and treatment is limited to supportive care to make breathing easier. In the rare most serious cases, patients are admitted to intensive care even though most people recover on their own.