Received: 25 January 2018
Accepted: 27 February 2019
First Online: 12 March 2019
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of the Asmara College of Health Sciences and Ministry of Health of the State of Eritrea. Consent to participate in this study was not obtained from donors since donation records were anonymized.
: Not applicable.
: The authors declare that they have no competing interests.
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