Increase in Human Parvovirus B19 Activity in the United States

CDC The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to notify healthcare providers, public health authorities, and the public about current increases in human parvovirus B19 activity in the United States. Parvovirus B19 is a seasonal respiratory virus that is transmitted through respiratory droplets by people with symptomatic or asymptomatic infection. In the first quarter of 2024, public health authorities in 14 European countries observed unusually high numbers of cases of parvovirus B19. In the United States, there is no routine surveillance for parvovirus B19, and it is not a notifiable condition. Recently, CDC has received reports indicating increased parvovirus B19 activity in the United States. Data include increased test positivity for parvovirus B19 in clinical specimens and pooled plasma from a large commercial laboratory, and reports of clusters of parvovirus B19-associated complications among pregnant people and people with sickle cell disease. The proportion of people with IgM antibodies, an indicator of recent infection, increased among all ages from <3% during 2022–2024 to 10% in June 2024; the greatest increase was observed among children aged 5–9 years, from 15% during 2022–2024 to 40% in June 2024. Among plasma donors, the prevalence of pooled samples with parvovirus B19 DNA >10⁴ IU/mL increased from 1.5% in December 2023 to 19.9% in June 2024.

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