While COVID-19 cases have fallen this spring, a new respiratory illness called human metapneumovirus is emerging in US hospitals.
Unusual spikes in cases of the virus, commonly referred to as HMPV, have been reported in recent months by the US Centers for Disease Control and Prevention’s respiratory virus surveillance systems.
In the four years before the pandemic, the weekly percentage of positive tests never reached higher than 7.7 percent across the country, according to CDC data. So far this year, HMPV positive rates rose to 19.6 percent for antigen tests and 10.9 percent for PCR tests in March.
The increase has prompted people to wonder about this lesser-known respiratory virus. Here’s what some Massachusetts experts say:
What is HMPV?
Discovered in 2001 and thought to have mutated from avian metapneumovirus, HMPV usually causes cold-like symptoms such as coughing, a runny nose, fever, and shortness of breath, according to Dr. Shira Doron, chief infection control officer for Tufts Medicine health system and hospital epidemiologist at Tufts Medical Center.
HMPV comes from the same family as respiratory syncytial virus, a common respiratory virus known as RSV. Dr. Sabrina Assoumou, an infectious disease specialist at Boston Medical Center and assistant professor of medicine at Boston University, said HMPV follows the seasonal cycle of other respiratory viral diseases where cases often peak from winter until spring.
According to the CDC, the virus spreads through coughing, sneezing, personal contact, and touching objects or surfaces that have the virus on them then touching the mouth, nose, or eyes.
Is there a way to prevent HMPV or treat those infected with HMPV?
There are no vaccines to prevent human metapneumovirus or direct treatment for the virus, Assoumou said. Those who are infected are limited to just treating their symptoms through over-the-counter medications.
Should we be concerned about HMPV?
While cases nationally have seen a spike, experts say that it isn’t a life-threatening virus and that most people will do fine as long as they are drinking plenty of fluids and resting.
“It’s just like a cold,” Assoumou said. “You should drink fluids and rest, and just take the same precautions of staying at home so you’re not spreading it.”
Assoumou said it is possible to develop complications from HMPV, such as pneumonia and lower respiratory infections. Those more at risk to these complications include younger children, the elderly, and those who are immunocompromised.
Are people usually tested for it?
Assoumou said doctors providing outpatient care generally don’t test people for HMPV because there is no commercially available testing that is widely accessible. Those who are hospitalized with pneumonia or lower respiratory infections are more likely to be tested for the virus.
Additionally, Assoumou said doctors often test for diseases and viruses that can be directly treated, and because there is no specific treatment for HMPV, testing doesn’t provide any clear-cut treatment apart from addressing individual symptoms.
Why has there been a surge in HMPV cases nationally?
Doron said the spike in HMPV cases could be the consequence of pandemic precaution measures, such as social distancing, COVID lockdowns, and wearing masks.
She explained that daily social interactions can help people develop immunity for common respiratory viruses. However, because most people were socially distant and stayed at home during the pandemic, many have less biological defenses to fend off these viruses.
“When people are inside for a long time and taking precaution for three years, you got a really good proportion of the population not having had any immunity and being susceptible to viruses,” Doron said. “So everyone gets it at once instead of a staggered fashion.”