CDC Warns Parvovirus B12 on the Rise

On Aug. 13, the U.S. Centers for Disease Control and Prevention (CDC) warned that a seasonal respiratory virus called parvovirus B19—also known as fifth disease or slapped cheek syndrome—has shown increased activity in the U.S. Parvovirus B19 is transmitted through respiratory droplets by people with symptomatic or asymptomatic infection.

As with many other illnesses, practices to prevent the spread of COVID-19 also reduced parvovirus B19 infections, which correlated to a loss of immunity, CNN reports.

In the first quarter of 2024, public health authorities in 14 European countries observed unusually high numbers of cases of parvovirus B19. In the U.S., the CDC has no routine surveillance for parvovirus B19, and it is not a notifiable condition.

Still, the CDC recently has received reports indicating increased parvovirus B19 test positivity rates along with clusters of complications among people with a high risk of severe illness. The proportion of people with antibodies, an indicator of recent infection, increased among all ages from less than 3% during 2022–2024 to 10% in June 2024. The most significant increase was observed among children aged 5 to 9 years, from 15% during 2022–2024 to 40% in June 2024. The prevalence of pooled samples among plasma donors with parvovirus B19 increased from 1.5% in December 2023 to 19.9% in June 2024.

Although many people with parvovirus B19 infection are asymptomatic, immunocompetent children and adults with symptomatic disease typically notice two phases of the disease. Symptoms of fever, myalgia, and malaise characterize the first phase of illness. During the second phase of illness (approximately seven to 10 days after the first phase), children often present with a characteristic facial rash or “slapped cheek” appearance. In immunocompetent adults, the most common symptoms of parvovirus B19 disease typically occur during the second phase and include a reticular rash on the trunk and joint pain.

No vaccine or specific treatment is recommended for parvovirus B19 infection.