What is human metapneumovirus?

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Some people on social media have been discussing human metapneumovirus, or HMPV.

Most people probably have not heard of the virus, but it’s no cause for alarm. It’s a respiratory illness that, for most who get it, will feel like a common cold.

Here are answers to common questions.

– What is human metapneumovirus?

Human metapneumovirus, which was discovered in 2001, is a paramyxovirus, a family of viruses known to cause a wide range of common infections. Other paramyxoviruses include parainfluenza, respiratory syncytial virus (RSV), measles and mumps.

“This one usually causes a cold – not a big deal in most individuals,” said Monica Gandhi, an infectious-disease expert at the University of California at San Francisco.

– Why are people talking about metapneumovirus?

Like other respiratory illnesses, cases of human metapneumovirus have been on the rise. The Centers for Disease Control and Prevention reported this month unusual spikes in cases this spring across the United States.

Virus experts have speculated that the surge in a number of viruses, including RSV, may be an aftereffect of covid lockdowns and masking. Small interactions with viruses prime our system to better handle future exposures to viruses. But after years of masking and social distancing in schools, children have fewer biological defenses to fend off multiple viruses at once.

– What are the symptoms of HPMV?

The virus, which usually makes its appearance in the winter and spring, most commonly affects the upper respiratory tract, causing nasal congestion, cough and shortness of breath, as well as fever. It typically lasts three to seven days.

– Is HPMV ever serious?

Human metapneumovirus is usually mild, but it can have more serious consequences for young children, older adults and those with weakened immune systems.

In some cases, it can progress to the lower respiratory tract, leading to a more severe illness such as bronchiolitis, which causes swelling, irritation and mucus buildup in the lungs, or pneumonia. Depending on the severity, the virus typically lasts the same amount of time as other viruses, about three to seven days, Gandhi said.

– How does HPMV spread?

Human metapneumovirus is spread similarly to other viruses – through airborne particles produced by coughing or sneezing, through physical contact with a person who has the virus, or handling contaminated objects and then touching the eyes, mouth or nose, according to the CDC.

Gandhi said it’s important to note that the virus can spread even when people are asymptomatic. In one study, asymptomatic human metapneumovirus infections accounted for at least 38 percent of infections.

“But the time you’re most infectious in all infectious diseases is when you’re having active symptoms because you’re spreading it – you’re coughing it out through your mouth, you’re sneezing it out through your nose,” she added.

– Is there a vaccine? How is HMPV treated?

There is no vaccine for human metapneumovirus, and treatment is limited to supportive care.

“We try to make you feel better and make sure that your breathing is okay while your body fights off the virus,” said William Schaffner, a professor of infectious diseases and preventive medicine at Vanderbilt University. Although rare, Schaffner said that in severe cases in which people are having difficulty breathing, “we can put them in an intensive care unit and treat them there,” but most people fully recover on their own.

Unlike the novel coronavirus and its variants that cause covid, human metapneumovirus is a respiratory virus that has been around for decades, Gandhi said.

“Hopefully, in the future, we will actually see advances against human metapneumovirus. But we’ve been living with it for a long time,” she said. “This is not one that is going to cause a pandemic.”