In the four years preceding the pandemic, positive results for HMPV testing typically peaked between 6.2 and 7.7 percent in the months of March and April, according to data from the CDC. However, as the COVID-19 pandemic gained momentum in the spring of 2020, HMPV incidence declined and remained low through May 2021.
According to Panagis Galiatsatos, MD, a pulmonary and critical care physician with Johns Hopkins Medicine in Baltimore and a medical spokesperson for the American Lung Association, says, “Human metapneumovirus has been around for a while, but these numbers are higher than they’ve been in the last few years, so the virus is drawing attention.”
Regardless of the rise in HMPV cases this spring, an epidemiologist with the CDC, Amber Winn, MPH, explains that the latest national surveillance data suggest HMPV activity is “now returning to patterns similar to trends observed during pre-pandemic years.”
HMPV Testing Is Not Common
HMPV, a member of the virus family that includes respiratory syncytial virus (RSV), was first identified in 2001 in the Netherlands, according to the CDC. Nonetheless, previous research involving archived blood samples has shown that the virus has been in circulation since at least the 1950s.
Due to its relatively recent recognition as a respiratory virus, healthcare professionals may not routinely consider or test for HMPV, also noted by the CDC.
An epidemiologist with the CDC, Heather Scobie, PhD, MPH, says, “However, healthcare professionals should consider HMPV testing during winter and spring, especially when HMPV is commonly circulating,”
HMPV Virus Is Similar to a Bad Cold
Similar to other viruses responsible for upper and lower respiratory infections, HMPV spreads through respiratory droplets generated by coughing and sneezing. Additionally, it can be transmitted through direct contact, like handshakes.
Research suggests that the virus can be passed along from an infected person even when they’re not exhibiting any symptoms, or if they are asymptomatic. “There’s a rather significant asymptomatic spread; about 40 percent of people with human metapneumovirus don’t know they have it, and they may be spreading it,” says Dr. Galiatsatos.
HMPV can survive on surfaces for an extended period of time, says the Wisconsin Department of Health Services, making it possible for individuals to contact the virus by touching contaminated surfaces and subsequently touching their eyes, nose, or mouth.
Although public health officials are choosing to keep a close eye on the disease, they also share that they are not yet alarmed. Normally, HMPV infections tend to cause mild symptoms, which include the following:
Dr. Galiatsatos also says, “For the general public, it’s going to feel like a bad cold, and probably one that’s a little more cough-centric. So you’re going to feel rather miserable, and HMPV can linger for some time, so that can be frustrating.”
But in some cases, the physical effects of HMPV may also be severe, leading to:
- difficulty breathing
- aggravation of asthma
According to the American Lung Association, in serious hospitalized cases, some doctors may choose to do a bronchoscopy, where they insert a small, flexible camera into the lung, taking a fluid sample to test for viruses.
Cleveland Clinic also suggests that while anyone can get HMPV, individuals at higher risk of complications from the virus include newborns, children under 5, seniors aged 65 and older, individuals with asthma who take steroids, COPD patients, and immunocompromised individuals, such as those undergoing cancer treatment or organ transplant recipients.
Supportive Treatment for HMPV Infections
There is no specific antiviral therapy or cure for HMPV at the moment, so treatment primarily focuses on symptom management. Recommended therapies include decongestants, fever reducers, antihistamines, and other measures to provide comfort until the illness subsides, including rest and adequate hydration.
Hospitalized individuals with HMPV may require supplemental oxygen and mechanical ventilation. Intravenous fluids may be administered for hydration in cases involving vomiting and diarrhea. For individuals with pre-existing conditions like asthma or chronic obstructive pulmonary disease (COPD), bronchodilators and steroids may be used to alleviate symptoms.
Dr. Galiatsatos suggests that doctors tend to test for flu, COVID-19, and to some extent, RSV, as these conditions have available treatments and vaccines. For instance, Tamiflu and Paxlovid are FDA-approvedantiviral drugs for acute flu and COVID-19, respectively. Vaccines are also accessible for these three viruses.
However, there is currently no vaccine for HMPV, though research is underway to develop one. In May, pharmaceutical company Icosavax reported positive results from early trials of its vaccine candidate designed to prevent RSV and HMPV infections in older adults.
As with other respiratory viruses, healthcare professionals recommend preventive measures to reduce the risk of illness. These precautions include covering one’s nose and mouth when coughing or sneezing, frequent hand-washing, refraining from touching the face with unwashed hands, and avoiding close contact with individuals who are sick.
As for Dr. Galiatsatos, he believes that the reason why HMPV case numbers have gone up this spring is that hospitals have been doing more intensive testing due to a rise in respiratory viruses in general.
“I think the interest comes on the heels of the pandemic at a time when we have been seeing a lot of people rather ill with respiratory infection,” he says.
It’s worth noting that respiratory viruses in general, including HMPV, have reemerged as pandemic precautions like masking and social distancing have been relaxed by the majority of the population. This relaxation of precautions may have contributed to the increased prevalence of HMPV infections.