Assessing B19V epidemiology and viremia dynamics in plasma donors: A comprehensive analysis.

BACKGROUND

Parvovirus B19 (B19V) infection is characterized by measurable bloodstream biomarkers, which vary over time indicating different phases of infection. High B19V DNA levels in the bloodstream are associated with infectivity, impacting the eligibility of source plasma donors.

OBJECTIVES

Characterize temporal changes in B19V epidemiological rates from January 2018 to April 2025 and to investigate the longitudinal dynamics of the diagnostic biomarkers and infectivity in subclinical infections among US source plasma donors.

RESULTS

B19V positivity rates in CSL's US source plasma donors decreased to a very low level during the COVID-19 pandemic and until Spring 2023 and re-emerged in two waves with peak rates ≥ 2.2-fold higher compared to pre-COVID data (2018 - 2020). During the exponential infection phase, B19V DNA doubled every 3-5 h, leading to high titers up to 10^12 IU/mL and peak infectivity of ∼10^8 TCID50/mL. Infectivity ceased when anti-B19V IgG reached a plateau or 14 days after DNA titer dropped below 4.8 × 10^5 IU/mL.

CONCLUSIONS

The re-emergence of B19V with high positivity rates highlights the relevance of donation testing for plasma. During the month from infection onset, B19V DNAemia correlates well with the measured infectious titer. B19V infectivity in plasma disappears within a month while DNA can persist in the plasma in absence of detectable infectivity, likely due to the immune response as characterized by the immunological markers.