Retrospective and Prospective Surveillance and Clinical Presentation of Parvovirus B19 in Veneto, Italy, 2024

The recent increase in parvovirus B19 (B19V) infections across Europe has underscored the need for enhanced surveillance. In Italy, B19V surveillance is not mandated nationally. This ambispective (retrospective and prospective) study aimed to assess the epidemiological and clinical characteristics of the 2024 apparent surge in the Veneto Region by implementing mandatory disease notification starting in May 2024 and collecting clinical data on confirmed cases. During the surveillance period, 3156 B19V cases were reported, with 2.9% (93/3156) requiring hospitalisation (95% CI 2.4-3.5%). Children under 1 year of age exhibited the highest hospitalisation rate (29.0%), followed by adults aged 18-40 (17.5%). Infections disproportionately affected children aged 1-5 and 6-11, and the Granger causality test showed that an increase in cases among the 1-5-year-olds was predictive of subsequent rises in other age groups (p = 0.0086). Severe complications, including myocarditis, pericarditis, and miscarriage, were observed, and one death occurred following cardiac and neurological complications in a patient without prior risk factors. The presence of concurrent pathologies, particularly haematological disorders, was associated with increased disease severity. These findings highlight the importance of early warning when cases begin rising among preschool-aged children and underscore the need for improved B19V awareness, particularly in high-risk populations. Future efforts should evaluate the feasibility of implementing a systematic, potentially EU-wide, surveillance for B19V.