Risks posed by reported increased circulation of human parvovirus B19 in the EU/EEA

Epidemiological situation

Since March 2024, nine EU/EEA countries have reported increased detections of B19V on the European surveillance portal for infectious diseases, EpiPulse, from a number of monitoring systems, mostly during late 2023 and early 2024. As a response to an inquiry from ECDC to the National Focal Points (NFPs) in the ECDC-SoHO network blood group [1] on B19V infections, 10 countries reported an increase in reactive tests for B19V in blood donors or in donations of plasma for fractionation during the first months of 2024 compared to the same period in 2023.

Risk assessment

Based on the unusually high numbers of B19V cases reported in 14 EU/EEA countries, the risk of infection is assessed in four population groups as follows:

• The risk for the general population is assessed as low, as most infections are in the form of a mild exanthematous disease of childhood, although some complications may occur.
• The risk for pregnant women, less than 20 weeks gestation is assessed as low to moderate, considering the uncertainties about the virus circulation, the fact that an estimated 30–40% of women of childbearing age are susceptible to the infection, and severe outcomes occur in a small percent of infected pregnancies.
• The risk for immunosuppressed people is assessed as moderate, as these patients cannot clear the infection and can suffer chronic anaemia, pancytopenia, graft loss or dysfunction and organ-invasive disease.
• The risk for people with chronic haematological diseases (e.g. sickle cell disease, thalassaemia, etc.) is assessed as moderate, as B19V infection can cause transient aplastic crisis.

Recommendations

For public health authorities

ECDC recommends that public health authorities in the countries should:

• Raise awareness among clinicians of the observed increase of B19V to assist in counselling and managing their patients appropriately.
• Conduct risk communication to the risk groups, including pregnant women, immunosuppressed and transplant recipients, and patients with chronic blood disorders, particularly haemolytic anaemias.
• Review, in a multidisciplinary collaboration, any available datasets collected on B19V infections going back to the years before the pandemic to establish trends and changes in patterns of transmission. Reporting these findings to EpiPulse will assist in improving the risk assessment and tailor the risk communication messages for all EU countries.

For SoHO professionals and competent authorities

• Additional systematic testing of blood donors for B19V infection is not required. However, if a B19V infection is suspected or confirmed for a donor, the B19V-positive blood or blood components should not be transfused to individuals susceptible to severe clinical outcomes of B19V infections, i.e. pregnant women, patients with chronic haemolytic diseases or hemoglobinopathies, or immunosuppressed people.