New atypical epidemiological profile of parvovirus B19 revealed by molecular screening of blood donations, France, winter 2023/24.

In France, blood donations are tested in pools of 96 samples for parvovirus B19 (B19V) DNA to discard plasma for fractionation when it contains high viral loads. Between January 2015 and March 2024, B19V-positive donations decreased during the COVID-19 pandemic, followed by a strong rebound in 2023 and unusually high circulation during winter 2023/24 (ca 10 times higher December 2023-March 2024 vs the pre-pandemic period). Variations over time are probably related to measures implemented to limit SARS-CoV-2 spread.

Low rate of RNAemia in blood donations collected during the first wave of COVID-19 in France.

BACKGROUND: To investigate the transmission of SARS-CoV-2 via blood, we conducted retrospective molecular screening in blood donated during the first pandemic peak in the two French regions with the highest community transmission. METHODS: Archived plasma samples randomly selected from donations collected between March 23 and 29, 2020, in Eastern and Northern regions of France were tested for SARS-CoV-2 RNA in minipools of 4 donations (MP4) using the Grifols ProcleixSARS-CoV-2 assay. Reactive MP4 and the four corresponding plasmas were further tested with alternative RT-PCRs and sequencing. Testing for SARS-CoV-2 antibodies and in vitro infectivity in cell culture were also performed. RESULTS: Among the 2818 MP4 (corresponding to 9672 donations) tested for viral RNA, 5 were weakly reactive. Among the 20 plasmas included in these five MP4, one presented low-level reactivity with RT-PCRs and Procleix SARS-CoV-2 and was confirmed on sequencing. The estimated prevalence was 1.03/10,000 (95% CI 0-3.1). The 20 plasmas were antibody nonreactive and none of them showed cytopathic effects in cell culture. When recalled, the index-donor declared having had symptoms compatible with SARS-CoV-2 infection a few days after donation. The two immunocompromised recipients transfused with red blood cells and an inactivated pooled platelet product did not develop COVID-19. CONCLUSION: Our results indicated a low prevalence of SARS-CoV-2 RNA in the plasma of asymptomatic blood donors during the pandemic peak and no evidence of infectivity in vivo and in vitro. The transfusion risk remains theoretical and does not justify the implementation of SARS-CoV-2 NAT for blood donations.

Hepatitis A: an epidemiological survey in blood donors, France 2015 to 2017.

Since mid-2016, hepatitis A virus (HAV) outbreaks, involving predominantly men who have sex with men (MSM), have affected countries in Europe and overseas. In France, HAV screening of blood donations in 2017 revealed a HAV-RNA prevalence ca fivefold higher than during 2015-16 (4.42/106 vs 0.86/106; p = 0.0005). In 2017, despite a higher male-to-female ratio (5.5 vs 0.7) and the identification of MSM-associated outbreak strains, only one of 11 infected male donors self-reported being a MSM.

Seven years (2015-2021) of blood donor screening for HEV-RNA in France: lessons and perspectives.

BACKGROUND: The French health authorities are considering expanding the current selective hepatitis E virus (HEV)-RNA testing procedure to include all donations in order to further reduce transfusion-transmitted HEV infection. Data obtained from blood donors (BDs) tested for HEV-RNA between 2015 and 2021 were used to assess the most efficient nucleic acid testing (NAT) strategy. MATERIALS AND METHODS: Viral loads (VLs) and the plasma volume of blood components, as well as an HEV-RNA dose of 3.85 log IU as the infectious threshold and an assay with a 95% limit of detection (LOD) at 17 IU/mL, were used to assess the proportion of: (i) HEV-RNA-positive BDs that would remain undetected; and (ii) blood components associated with these undetected BDs with an HEV-RNA dose >3.85 log IU, considering 4 NAT options (Individual testing [ID], MP-6, MP-12, and MP-24). RESULTS: Of the 510,118 BDs collected during the study period, 510 (0.10%) were HEV-RNA-positive. Based on measurable VLs available in 388 cases, 1%, 15.2%, 21.8%, and 32.6% of BDs would theoretically pass undetected due to a VL below the LOD of ID, MP-6, MP-12, and MP-24 testing, respectively. All BDs associated with a potentially infectious blood component would be detected with ID-NAT while 13% of them would be undetected with MP-6, 19.6% with MP-12, and 30.4% with MP-24 depending on the plasma volume. No red blood cell (RBC) components with an HEV-RNA dose >3.85 log IU would enter the blood supply, regardless of the NAT strategy used. DISCUSSION: A highly sensitive ID-NAT would ensure maximum safety. However, an MP-based strategy can be considered given that: (i) the risk of transmission is closely related to the plasma volume of blood components; (ii) RBC are the most commonly transfused components and have a low plasma content; and (iii) HEV-RNA doses transmitting infection exceed 4 log IU. To minimise the potential risk associated with apheresis platelet components and fresh frozen plasma, less than 12 donations should be pooled using an NAT assay with a LOD of approximately 20 IU/mL.