What to Know About Human Metapneumovirus (HMPV)
A lesser-known respiratory virus is seeing increased activity across the U.S. Cases of Human metapneumovirus (HMPV) have been on the rise since fall 2025, with recent data from the Centers for Disease Control and Prevention showing it accounted for about 5% of positive respiratory virus tests nationwide in early March. Wastewater surveillance has also detected activity in multiple regions, including northern California, suggesting the virus is circulating more widely.
While HMPV is not new (it often causes mild, cold-like symptoms), it can lead to more serious illness in certain populations. The virus is related to RSV (Respiratory Syncytial Virus), and like other seasonal respiratory infections, it’s something clinicians are continuing to monitor.
To better understand what this means for our community, we spoke with Eriko Masuda, MD, an infectious disease expert with Torrance Memorial Health.
Q: HMPV symptoms sound a lot like other respiratory illnesses. How can clinicians tell the difference between HMPV, RSV (Respiratory Syncytial Virus), or influenza?
Dr. Masuda:
It is difficult to distinguish human metapneumovirus from other viruses based on symptoms. They can all cause fevers, cough, nasal congestion and sore throat.
Q: Are you seeing any changes in how HMPV is showing up compared to previous years?
Dr. Masuda:
During the pandemic, people stayed home and natural immunity waned. We’re seeing longer viral seasons as a result.
Q: Who is most at risk—and are there people who may not realize they’re vulnerable?
Dr. Masuda:
The same high-risk groups are at risk for severe infection from human metapneumovirus. This includes the elderly, young children, transplant recipients, patients receiving chemotherapy or high-dose steroids, and patients with HIV.
Q: How does HMPV affect people with underlying conditions like asthma or Chronic obstructive pulmonary disease?
Dr. Masuda:
It can exacerbate their chronic condition, especially underlying pulmonary diseases. Patients with weakened immune systems can develop complications like pneumonia and sepsis.
Q: Is HMPV more contagious than other respiratory viruses?
Dr. Masuda:
There is no evidence that HMPV is more contagious than other viral infections.
Q: When should someone be tested specifically for HMPV?
Dr. Masuda:
Testing should be considered when patients develop severe symptoms or are not improving. It is most useful to rule out other possible infections.
Q: With no specific antiviral treatment, how is HMPV managed?
Dr. Masuda:
Like other viral illnesses, treatment focuses on rest, hydration, and a healthy diet. Rest is especially important to prevent worsening.
Q: When should someone seek medical care instead of recovering at home?
Dr. Masuda:
You should seek care if symptoms are not improving after several days, or if you experience shortness of breath, persistent high fevers, inability to stay hydrated, or chest pain. This is especially important for small children, the elderly, and those with underlying health conditions.
Q: For parents, how does HMPV compare to RSV?
Dr. Masuda:
RSV tends to affect younger children and can cause more severe disease than human metapneumovirus.
Q: Can children get HMPV more than once?
Dr. Masuda:
Yes, patients can be reinfected during the same respiratory season due to multiple different strains circulating.
Q: What prevention strategies actually make a difference?
Dr. Masuda:
Washing your hands, avoiding touching your face, staying home when sick, and cleaning frequently touched surfaces are the most effective ways to reduce spread.
Q: Are vaccines or new treatments on the horizon?
Dr. Masuda:
There are several vaccine candidates currently in development. Some are in early phase clinical trials.
Q: Are you seeing HMPV cases locally right now?
Dr. Masuda:
Yes, we are finding patients testing positive both in clinic and in the hospital. Most hospitalized patients have underlying conditions, such as transplant recipients.
While Human metapneumovirus may not be as widely recognized as flu or RSV, it’s a common respiratory virus that can lead to serious complications in vulnerable populations. With longer viral seasons and ongoing circulation in the community, staying vigilant about symptoms—and practicing simple prevention measures—can go a long way in protecting yourself and others.
Dr. Eriko Masuda, MD is an infectious disease internist with more than 10 years of experience in the medical field. She graduated from University of Miami Miller School of Medicine in 2014. She is a former faculty member of the MLK Community Healthcare Internal Medicine Residency Program. She is accepting new patients and can be reached at 310-784-6954.
