Human parvovirus B19, commonly referred to as "slapped cheek disease," is seeing a significant uptick across the United States, especially in young children. This highly contagious respiratory infection is typically mild for healthy individuals but can pose serious risks to certain vulnerable groups.
On Tuesday, the U.S. Centers for Disease Control and Prevention (CDC) issued a health advisory, alerting the public to a noticeable rise in parvovirus B19 cases. The most pronounced increase has been observed among children aged five to nine.
According to the CDC, the percentage of Americans with antibodies for parvovirus B19, indicating recent infection, jumped from under 3% during 2022–2024 to 10% by June 2024. Among children aged five to nine, this figure surged from 15% to 40%.
The CDC has also received reports of clusters of parvovirus B19-related complications, particularly affecting pregnant individuals and those with sickle cell disease.
This advisory follows reports from European health authorities, who have documented unusually high numbers of parvovirus B19 cases across 14 countries in the first quarter of 2024.
Understanding Parvovirus B19: What It Is, Symptoms, and Transmission
What is Human Parvovirus B19?
Human parvovirus B19 is a common, highly contagious respiratory infection that tends to be seasonal, with peaks in late spring and summer. Dr. William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center, explains that the infection is often called "slapped cheek disease" due to the distinct facial rash it causes. It’s also known as "fifth disease," a term derived from its place on a historical list of childhood illnesses that cause rashes.
"Infections are most prevalent in children, which is usually when most of us first encounter the virus," says Schaffner. For the majority, a parvovirus B19 infection is either mild or goes unnoticed.
The Mayo Clinic notes that many adults in the U.S. are immune to parvovirus, likely due to an unnoticed infection during childhood. The CDC reports that around 50% of adults have antibodies to parvovirus B19 by age 20, with this figure rising to about 70% by age 40.
While the virus is typically mild, it can cause more severe illness in adults without prior immunity, particularly in women. Serious complications can occur in specific groups, including pregnant individuals, those with weakened immune systems, and people with certain blood disorders.
How Does Parvovirus B19 Spread?
Parvovirus B19 is easily spread from person to person via respiratory droplets, which are expelled when an infected individual coughs or sneezes. The CDC emphasizes that close personal contact is the most common mode of transmission.
“Children are often the primary spreaders, typically catching the virus at school and bringing it home,” Schaffner notes.
Less commonly, the virus can be transmitted from mother to fetus during pregnancy or through blood transfusions.
What Are the Symptoms of Parvovirus B19?
Most people infected with parvovirus B19 show no symptoms. When symptoms do occur, they are generally mild and resemble flu-like illnesses. Common symptoms include:
- Fever
- Headache
- Cough
- Sore throat
- Runny nose
- Rash
- Joint pain
A distinctive "slapped cheek" rash may appear later in the illness, particularly in children. This rash can spread to the chest, back, torso, arms, and legs, sometimes becoming itchy.
While the rash usually clears up within a week to 10 days, it can persist or recur for several weeks before completely disappearing. Factors such as exercise, exposure to heat or sunlight, or emotional stress may exacerbate the rash.
Joint Issues
Adults infected with parvovirus B19 are less likely to develop the facial rash but may experience joint pain and swelling, which can resemble rheumatoid arthritis. These symptoms can last from a few weeks to several months but typically resolve without permanent joint damage.
Parvovirus B19 Complications
Most people fully recover from parvovirus B19. However, the infection can lead to complications in pregnant individuals, those with weakened immune systems, or individuals with specific blood disorders who have never been exposed to the virus.
In rare cases, the virus can cross the placenta during pregnancy, potentially leading to fetal anemia or miscarriage. The risk is highest when infection occurs between nine and 20 weeks of gestation, with adverse outcomes occurring in about 5% of pregnant women.
For people with weakened immune systems or certain blood disorders, parvovirus B19 can cause chronic anemia or a significant drop in blood counts. This includes cancer patients, individuals with HIV, organ transplant recipients, and those with sickle cell disease.
Parvovirus Treatment
Most individuals infected with parvovirus B19 recover fully on their own. There is no specific antiviral treatment for the virus, so care focuses on relieving symptoms. This may include over-the-counter pain relievers or fever reducers, and supportive care. Those with anemia may require blood transfusions or other medical interventions.
Can Pets Get Parvovirus?
While the term "parvovirus" is used for both human and animal infections, human parvovirus B19 is different from the type that affects animals like dogs. The Cleveland Clinic clarifies that parvovirus does not transmit between humans and pets.
Canine parvovirus type 2 (CPV-2) is a highly contagious virus that spreads among dogs, particularly causing severe gastrointestinal illness in puppies.
How to Prevent Parvovirus
There is currently no vaccine to prevent parvovirus B19. However, practicing good hygiene and taking measures to prevent respiratory infections can help reduce the risk. The CDC recommends:
- Frequent handwashing
- Covering your mouth and nose when coughing or sneezing
- Avoiding close contact with sick individuals
- Keeping sick children at home