Severe Presentations and Outcomes in Hospitalized Pediatric Patients With Parvovirus B19 Infection During the 2024 Outbreak: A Multicenter Prospective Study in Italy

Background: Since March 2024, the European Center for Disease Prevention and Control has reported increased Parvovirus B19 (B19V) infections across 14 European countries. While often self-limiting in healthy children, B19V may cause severe disease in vulnerable populations. Methods: This multicenter prospective study aimed to characterize the clinical presentation of B19V infection in hospitalized children and identify risk factors for severe outcomes. Data were collected through the INF-ACT pediatric surveillance system, as part of the National Recovery and Resilience Plan. Children hospitalized with confirmed B19V infection were enrolled from January to December 2024 in 10 Italian INF-ACT centers. Results: A total of 135 children were included (median age 7.6 years, interquartile range 4.4-9.9), with 78.5% of cases occurring between April and July 2024. Acute myocarditis (20.7%) and neurologic complications (17.8%) were the most frequent severe manifestations. Myocarditis was significantly associated with younger age ( P < 0.001), longer hospital stays (median 19.5 vs. 6.5 days; P = 0.0018) and higher intensive care unit (ICU) admission rates (71.4% vs. 20.8%; P < 0.001). Multivariate analysis showed myocardial involvement increased the risk of ICU admission over 20-fold ( P < 0.001). Conclusions: Although often mild, B19V infection can cause severe complications in children, particularly myocarditis and neurologic involvement. Prompt recognition is essential, even in the absence of classic features like erythema infectiosum, to ensure timely monitoring and management of potentially life-threatening outcomes.