Diverse clinical manifestations of Parvovirus B19 infections during the 2024 outbreak in Germany.

Purpose: In 2024, human parvovirus B19 (PB19V) infections have increased in Germany and globally. It is an infection associated with a broad spectrum of clinical manifestations. To raise awareness, we present representative cases and virological data from different specialties across three German university hospitals.

Methods: Following a nationwide survey by the AGIHO in March 2024 indicating increased PB19V infections, we conducted a retrospective, multi-center descriptive study across Munich, Cologne, and Magdeburg. Anonymized clinical and virological data from 2022 to 2024 were collected, including patient demographics, underlying diseases, and diagnostic findings. Acute PB19V infection was defined by real-time quantitative PCR-based detection of PB19V DNA in any specimen.

Results: Clinical manifestations of acute PB19V infections can range from severe anemia and pancytopenia in hematologic patients, to fetal hydrops in pregnant women, and systemic inflammatory symptoms in patients with chronic conditions. In 2024, the Max von Pettenkofer Institute in Munich conducted 936 PB19V PCR tests. A marked increase in positive cases was observed in early 2024, with positivity rates of 16% in Q1 and 18.2% in Q2, compared to an annual positivity rate of 2.3% in 2023. Similar trends were seen at the University Hospitals Cologne and Magdeburg. Most infections were acute with high viral loads. Most cases originated from pediatric, gynecologic, and hematologic departments, highlighting particularly vulnerable patient populations.

Conclusions: This resurgence in symptomatic PB19V infections, likely driven by pandemic-related shifts in immunity and exposure, underscores the need for heightened clinical awareness, early testing in high-risk populations, and sustained surveillance to anticipate future outbreaks.