[1] Canadian Blood Serv, Epidemiol & Surveillance, Ottawa, ON K1G 4J5, Canada
[2] Univ Ottawa, Sch Epidemiol & Publ Hlth, Ottawa, ON K1G 192, Canada
[3] Queens Univ, Ctr Studies Primary Care, Dept Family Med, Kingston, ON K7L 3N6, Canada
[4] Canadian Blood Serv, Donat & Policy Studies, Ottawa, ON K1G 4J5, Canada
[5] Univ Ottawa, Fac Med, Dept Pathol & Lab Med, Ottawa K1G 192, ON, Canada
[6] Canadian Blood Serv, Microbiol, Edmonton, AB T6G 2R8, Canada
[7] Univ Alberta, Fac Med & Dent, Dept Lab Med & Pathol, Edmonton, AB T6G 2E1, Canada