New findings from investigators at American Red Cross, Bloodworks Northwest, New York Blood Center and Vitalant confirmed that plasma collected from donors with pre-symptomatic COVID-19 continues to be highly unlikely to transmit SARS CoV-2 infection. Investigators published their findings, conducted as part of the REDS-IV-P program, in the Journal of Clinical Investigation.
Although there has been no evidence of transfusion-transmitted SARS-CoV-2 resulting in COVID-19, investigators sought to assess to what degree SARS-CoV-2 could potentially find its way into the blood supply from pre-symptomatic donors, and what if any impact it could have on patient care. To do so, they tested 2,250 quarantined plasma samples from blood donors who reported possible COVID-19 infection within 14 days of their plasma donation for the presence of SARS-CoV-2 RNA.
Of the 2,250 samples tested, 196 (8.7%) were RNA repeat reactive, with RNA prevalence increasing from 1% in March 2020 to 15% in March 2021. The median estimated viral load in the 196 RNA repeat-reactive plasma samples was 6 gEq/mL, with 90% of samples having an estimated viral load of 18 gEq/mL or lower. No infectious virus was detected in plasma from RNAemic donors. To address the theoretical risk of transfusion transmission of COVID-19, investigators tested the ability of plasma from RNA-positive units to infect a permissive cell line in vitro and an engineered mouse model in vivo. Inoculation of permissive cell lines produced less than 0.7–7 plaque-forming units (PFU)/mL and in susceptible mice less than 100 PFU/mL in RNA-positive plasma based on limits of detection in these models. According to the authors, the findings suggest that blood transfusions are highly unlikely to transmit SARS-CoV-2 infection.
