[1] British Columbia Canc Agcy, Hlth Econ, Vancouver, BC V5Z 4E6, Canada
[2] BC Ctr Dis Control, STI Div, Vancouver, BC, Canada
[3] BC Ctr Dis Control, Hepatitis Div, Vancouver, BC, Canada
[4] Univ British Columbia, Fac Med, Vancouver, BC, Canada
[5] British Columbia Canc Agcy, Populat Oncol, Vancouver, BC V5Z 4E6, Canada
[6] McGill Univ Epidemiol, Montreal, PQ, Canada