NAT screening of blood donors for severe acute respiratory syndrome coronavirus can potentially prevent transfusion associated transmissions

Abstract

Background: The severe acute respiratory syndrome (SARS) was first described in February 2003. Close contact with symptomatic patients appears to be the main route of transmission, whereas blood transfusion transmission could not be ruled out.

Study design and methods: A SARS coronavirus (SARS-CoV) detection kit developed by C. Drosten (Bernhard Nocht Institute, BNI) was used to amplify SARS-CoV sequences from blood donor samples. We tested 31,151 blood donor samples in minipools of up to 96 samples. To validate the sensitivity of the assay, routine donor minipools (88 +/- 8 samples per pool) were spiked with plasma of an imported case of SARS or of a subsequently infected contact person, respectively. Gamma-irradiated cell culture supernatants of Vero E6 cells, infected with SARS-CoV, were used as positive controls.

Results: None of 31,151 blood donors were positive for the presence of SARS. Two 96-member plasma pools that were each spiked with 100 microL of plasma of the German index patient or his wife, respectively, were positive. Overall, 0.85 percent of test results had to be considered invalid owing to negative internal controls.

Conclusion: A real-time CoV PCR test is able to detect SARS-CoV in viremic blood donor samples even in the beginning of the disease when patients present minor clinical symptoms. Thus the assay could potentially help to prevent transfusion-associated SARS-CoV transmissions.

Figure 1

Course of the disease. Patient 1 was a 32‐year‐old physician from Singapore, and Patient 2 was his 30‐year‐old wife. Plasma sample was taken from Patient 1 on Day 10 and from Patient 2 on Day 3 of disease.

Figure 2

Linear range of the SARS LC test. Correlation between nominal SARS RNA concentration and measured SARS RNA concentration of the internal standard. Each concentration was analyzed in 10 independent PCR procedures. y = 1.0965x – 52.74; R²= 0.995.

Figure 3

Real time PCR of SARS‐CoV in two patients. (I) 100 µL of plasma from Patients 1 and 2, collected from Day 10 (Patient 1) and Day 3 (Patient 2) ( Fig. 1 ) of the disease, was spiked into 9.5‐mL HIV‐1‐, HBV‐, HCV‐, HAV‐, parvovirus B19‐, HBsAg‐, and Treponema pallidum hemagglutination assay‐negative donor plasma pools and analyzed by pool PCR. (II) 100 µL of plasma from Patient 1 and 2 was measured by single‐donor PCR. A = Standard 1 (10² copies/µL); B = Standard 2 (10¹ copies/µL); C = Patient 2; D = Patient 1; E = no template control.