key: cord-0988968-aijrydzk
authors: Loubaki, Lionel; Gantner, Pierre; Pagliuzza, Amélie; Fausther‐Bovendo, Hugues; Kobinger, Gary; Chomont, Nicolas; Germain, Marc
title: Testing for the presence of SARS‐CoV‐2 RNA in presymptomatic blood donors
date: 2021-02-12
journal: Transfusion
DOI: 10.1111/trf.16155
sha: 40473c6fb61f9317869e799671764083ce2d9a5a
doc_id: 988968
cord_uid: aijrydzk

nan

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. The breadth of symptoms greatly varies in SARS-CoV-2-infected individuals, some may be asymptomatic, while other may experience a combination of cough, fever, and breathing difficulties associated with pneumonia in both lungs. 1 In addition, symptoms can take up to 14 days to appear after exposure to SARS-CoV-2. 1 SARS-CoV-2 RNA can initially be detected in the upper respiratory tract, 1 to 2 days before the onset of symptoms. The virus can persist for 7 to 12 days in moderate cases and up to 2 weeks in severe cases. 1 Furthermore, patients with few or no symptoms have detectable levels of viral RNA in the oropharynx highlighting the potential for virus transmission during the incubation period. 2 SARS-Cov-2 RNA can also be detected in the blood of a small proportion of people with COVID-19 1,3,4 but the presence of SARS-CoV-2 RNA and infectious virions in blood during the presymptomatic period of infection remains to be established. At Héma-Québec, from the start of the pandemic, we implemented precautionary measures to reduce the theoretical risk of transmission of SARS-CoV-2 by blood transfusion. Among those measures, all donations from donors who reported symptoms related to COVID-19 in the next 3 days after their donation were recalled from the hospital or withdrawn from the inventory, whether or not a diagnosis of COVID-19 was confirmed at that time. If the COVID-19 diagnosis was confirmed, the implicated units were included in this study. For some other donations, Héma-Québec was directly alerted by public health authorities after a confirmed COVID-19 diagnosis. Again, such products were specificity of the assay. The primer and probe sequences, used by the four laboratories, are listed in Table 2 . Among the six samples tested, only one was found to be weakly positive for the E gene (36.1 cycle threshold; cycle threshold of a positive result was ≤40) by two of the four testing centers (Table 1) . This was a plasma donation dedicated to fractionation. This discrepancy among the testing laboratories was related to the volume of plasma used to isolate the viral RNA. Indeed, by using a larger (up to 280 μL vs 140 μL) volume of plasma during the viral RNA isolation, these two laboratories were able to get a weak positive result by PCR. The infectivity of the SARS-CoV-2 found in this donation was evaluated using Vero E6 cell line 5 and was found to be noninfectious. A plasma donation given 6 days earlier by this same donor was also recalled, tested, and found to be negative for SARS-CoV-2 RNA. Interestingly, for the donor who had mild symptoms at the time of her donation, this latter was tested negative for the presence of SARS-CoV-2 RNA. All six donors were also tested for the presence of antibodies against SARS-CoV-2 and all were negative, confirming that they were in the early phase of infection. These results are consistent with those reported by Chang and colleagues from China, 4 where only four donors out of more than 7000 were found to be weakly positive for SARS-CoV-2 RNA in their blood.

In conclusion, our data indicate that SARS-CoV-2, like other respiratory viruses such as SARS-CoV and MERS-CoV, is present in very limited amount if not totally absent in blood products donated shortly before the onset of symptoms in infected individuals. Consequently, the risk of transmission of COVID-19 by blood transfusion, if it exists, would appear to be negligible.

To the Editor Convalescent plasma, collected from donors who have previously recovered from viral illnesses, has been used to treat patients with a variety of emerging infectious diseases. This product has become more prominent during the current COVID-19 pandemic, including with the recent emergency use authorization from the Food and Drug Administration, but the longevity of

Report of the WHO-China joint Mission on coronavirus disease 2019 (COVID-19)

SARS-CoV-2 viral load in upper respiratory specimens of infected patients

Post-donation COVID-19 identification in blood donors

Severe acute respiratory syndrome coronavirus 2 RNA detected in blood donations

SARScoronavirus-2 replication in Vero E6 cells: replication kinetics, rapid adaptation and cytopathology

The authors have disclosed no conflicts of interest.