Human parvovirus B19 activity is on the rise in the U.S., particularly among children, the CDC said in an Aug. 13 health alert.
Parvovirus B19 is a highly contagious respiratory virus that typically causes mild illness, but poses risks for severe outcomes in those who do not have pre-existing immunity, are immunocompromised and those who are pregnant. The agency said it has received data that shows less than 3% of people had antibodies to suggest recent infection in 2022, which rose to 10% in 2024. Among children aged 5 to 9, this rose from 15% to 40%.
The agency said it has also received anecdotal reports from clinicians regarding a higher than expected number of cases among pregnant people, including complications such as severe fetal anemia or miscarriage, and increases in aplastic anemia in patients with sickle cell disease.
Most people who are infected do not develop symptoms. Those who do may experience fever, fatigue and muscle aches. In children, the second phase of the illness is typically marked by a characteristic facial rash that gives the infection its "slapped cheek disease" nickname.
Clinicians should especially watch for parvovirus B19 infections among those with related symptoms, the agency said. There is no routine surveillance for the virus in the U.S. and it is not a notifiable condition, so providers and public health departments should be aware of rising activity and identify those at higher risk of severe outcomes.