While cases of COVID-19 and RSV have declined in recent months, another, lesser-known respiratory virus emerged this past spring.
A May 31 report from the Centers for Disease Control and Prevention (CDC) showed that positive PCR lab tests for human metapneumovirus (HMPV) in early March reached nearly 11 percent.
During the four years leading up to the pandemic, positive HMPV test results peaked between 6.2 and 7.7 percent in March and April, according to the CDC. With the outbreak of the epidemic in the spring of 2020, HMPV decreased and remained low through May 2021.
says Panagis Galiatsatos, MD, a pulmonologist and critical care physician at Johns Hopkins Medical Center in Baltimore and a medical spokesperson for the American Lung Association.
HMPV testing is not common
A member of the family of viruses that also includes respiratory syncytial virus (RSV), HMPV is relatively new as it was first discovered in 2001 in the Netherlands, according to the CDC. However, testing of archived blood samples showed that the virus had been circulating since at least the 1950s, according to previous research.
Because HMPV is a recently recognized respiratory virus, healthcare professionals may not routinely consider or test for HMPV, says the CDC.
“However, healthcare professionals should consider testing for HMPV during the winter and spring, especially when HMPV is most commonly circulating,” the CDC advises.
HMPV is similar to the common cold
Like other viruses that cause upper and lower respiratory infections, HMPV is spread through respiratory droplets from coughs and sneezes. People can also transmit it through contact such as shaking hands.
Research indicates that the virus can be transmitted from an infected person even when they are asymptomatic, or asymptomatic. “There is significant asymptomatic spread; about 40 percent of people infected with HCV do not know they have it and may be spreading it,” Dr. Galiatsatos says.
HMPV can also survive on surfaces for several hours, according to the Wisconsin Department of Health Services. This means that individuals can become infected by touching contaminated surfaces and then touching their mouth, nose, or eyes.
Public health officials monitor the disease but aren’t overly concerned. HMPV infection usually causes mild symptoms, including:
“For the general public, it will feel like a severe cold, maybe a little more than a cough-based cold,” says Galiatsatos. “So you’re going to feel somewhat miserable, and HMPV can stay for a while, so that can be frustrating.”
However, in some cases, the physical effects of the disease can be severe and lead to:
- zoom
- difficulty breathing
- Hoarseness
- worsening of asthma;
- vomiting
- Diarrhea
It is also possible for the disease to develop into bronchitis or pneumonia, which may require hospitalization.
The American Lung Association notes that in serious cases in the hospital, doctors can perform a bronchoscopy, in which a small, flexible camera is inserted into the lung and a sample of fluid is removed to test for viruses.
Anyone can get HMPV, but the Cleveland Clinic says those most at risk of complications are newborns, children under 5, older adults ages 65 and older, individuals with asthma who take steroids, chronic obstructive pulmonary patients, and those with chronic obstructive pulmonary disease. Those who are immunocompromised, such as those who are taking cancer medications or have undergone an organ transplant.
Get supportive treatment for HMPV infection
There is no specific antiviral treatment or treatment for HMPV, so most treatments are supportive. Recommended treatments include decongestants, fever reducers, antihistamines, and other means of providing relief until the illness resolves, such as rest and plenty of fluids.
People who are hospitalized with HMPV may need supplemental oxygen and assisted ventilation. When vomiting and diarrhea occur, intravenous fluids may be used for hydration. If HMPV worsens asthma or chronic obstructive pulmonary disease (COPD), bronchodilators and steroids may relieve symptoms.
Galiatsatos suggests that doctors tend to test for influenza, COVID-19, and RSV (to some extent) because there are treatments and vaccines available: The FDA has approved Tamiflu as an oral antiviral for severe influenza and Paxlovid for COVID-19. 19. In addition, there are now vaccines for all three.
Currently, there is no vaccine for HMPV, but at least one is in the pipeline. In May, the drug company Icosavax announced positive results from early trials of its vaccine candidate for prevention of RSV and HMPV in the elderly.
As with other respiratory viruses, health professionals encourage the public to take precautions to prevent getting sick in the first place. These measures include covering your nose and mouth when sneezing or coughing, washing hands frequently, not touching your face with unwashed hands, and avoiding close contact with sick people.
As for why the number of cases rose last spring, Galitsatos speculates that hospitals are doing more extensive testing because of the rise in respiratory viruses in general. “I think the interest comes in the wake of the pandemic at a time when we’re seeing a lot of people have some kind of respiratory infection,” he says.
In addition, respiratory viruses in general have re-emerged after most people abandoned pandemic precautions, such as masking and social distancing. This may also have contributed to the high incidence of HMPV.
