Sick days are on the rise again in Bay Area offices and classrooms.
But many people who test negative for COVID-19 and the flu may be dealing with something else: a respiratory virus that many Americans may have never heard of — human metapneumovirus (HMPV).
This virus is not new. Scientists first discovered it in 2001, and it spreads seasonally in the United States, usually from winter to spring, according to the Centers for Disease Control and Prevention.
This year, surveillance data and wastewater monitoring indicate that HMPV is widespread in parts of Northern California, including San Francisco and parts of the Bay Area.
The virus is difficult to detect because its symptoms are very similar to other respiratory illnesses.
HMPV is often similar to RSV, said Dean Blumberg, chief of the Division of Pediatric Infectious Diseases at UC Davis Health.
“This includes upper respiratory symptoms, sometimes progressing to pneumonia or bronchiolitis and wheezing,” he said.
Below is information about the virus.
What is human metapneumovirus (HMPV)?
Human metapneumovirus is a respiratory virus that can cause upper and lower respiratory tract illness in people of all ages, according to the Centers for Disease Control and Prevention. It belongs to the same virus family as respiratory syncytial virus (RSV).
Is HMPV spreading in Northern California?
Wastewater monitoring found elevated levels of HMPV in several Northern California communities, including San Francisco, Sacramento, Davis and Vallejo, according to the national wastewater monitoring program WastewaterSCAN.
Even if individuals are not tested, wastewater testing can help track the spread of the virus in the community.
Why are people hearing about HMPV now?
HMPV has been circulating for decades but is not as widely known as influenza, COVID-19, or RSV.
Public health experts say many cases may go undiagnosed because the symptoms are virtually indistinguishable from other respiratory infections.
Increased surveillance of respiratory viruses since the COVID-19 pandemic has also drawn increased attention to viruses such as HMPV.
What are the symptoms of HMPV?
Symptoms often include:
The CDC says that in some cases, especially in susceptible patients, the infection may progress to bronchitis or pneumonia.
Who is most likely to become seriously ill?
Most infections are mild, but certain groups are at higher risk of complications.
According to the CDC, high-risk groups include:
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Infants and children under 2 years old
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People with weakened immune systems
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People with underlying lung or heart disease
How does HMPV spread?
HMPV is spread similarly to other respiratory viruses.
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The CDC says transmission can occur through:
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Respiratory droplets from coughing or sneezing
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close personal contact, such as touching or shaking hands
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touching a contaminated surface and then touching your mouth, nose or eyes
Is there a vaccine or treatment for HMPV?
According to the CDC, there is currently no vaccine and no specific antiviral treatment for HMPV.
Treatment usually focuses on relieving symptoms. Most people recover on their own with rest, fluids, and supportive care.
How to reduce the risk of infection?
Public health experts recommend taking many of the same precautions as for other respiratory illnesses:
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Clean frequently touched surfaces
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Improve ventilation of indoor spaces
When should people seek medical care?
UC Davis Health recommends contacting your doctor if symptoms become severe or unusual.
Warning signs may include:
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Symptoms persist for more than 10 days
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Fever or unusual sleepiness in infants under 3 months old
This article was originally published on A little-known virus is spreading in Northern California. Here’s what you need to know.
