Parvovirus B19 infections in paediatric sickle cell disease patients: Genotype and hydroxyurea treatment influence disease severity.

In patients with sickle cell disease (SCD), parvovirus B19 infection (B19V) leads to acute anaemia (aplastic crisis), but may also be associated with other serious complications. We retrospectively analysed clinical data from paediatric SCD patients with B19V infections between 2023 and 2025, including symptoms, laboratory parameters, diagnostic procedures and treatment details to detect differences between SCD genotypes (HbSS and HbS/β0-thalassaemia, i.e. HbSS/Sβ0, and HbSC) and to determine the effect of hydroxyurea (HU; hydroxycarbamide) treatment in HbSS/Sβ0 patients. Ninety-eight patients (76 HbSS/Sβ0, 22 HbSC) were included in the study. There were significant differences in the symptoms of infection between genotypes, with a high prevalence of back pain as well as higher C-reactive protein and lactate dehydrogenase levels in HbSC. HbSC patients also received chest X-ray more frequently and required longer inpatient treatment. In addition, HbSC patients showed a significantly higher rate of immunoglobulin G seroconversion at the onset of symptoms, suggesting that antibody formation influences clinical appearance. In HbSS/Sβ0 patients, HU treatment was associated with higher haemoglobin and reduced transfusion requirements, but more frequently with neutropenia. In summary, B19V infections induce different clinical presentations depending on SCD genotypes, with HbSC patients showing a distinct phenotypic presentation. HU treatment reduces the need for transfusions in patients with HbSS/Sβ0.