[1] BC Ctr Dis Control, British Columbia Canc Agcy, Vancouver, BC V5Z 4E6, Canada
[2] Univ British Columbia, Dept Med, Vancouver, BC V5Z 1M9, Canada
[3] Univ British Columbia, Dept Pathol & Lab Med, Vancouver, BC V5Z 1M9, Canada
[4] BC Ctr Dis Control, Dept Epidemiol & Res, Vancouver, BC V5Z 4E6, Canada
[5] BC Ctr Dis Control, Dept Med Virol, Vancouver, BC V5Z 4E6, Canada