[1] Univ Toronto, Dept Med, Div Respirol, Toronto, ON, Canada
[2] Univ Hlth Network, Dept Med, Toronto, ON, Canada
[3] Mt Sinai Hosp, Toronto, ON, Canada
[4] West Pk Healthcare Ctr, Div Resp Med, Toronto, ON, Canada
[5] ICES, Toronto, ON, Canada
[6] Publ Hlth Ontario, Toronto, ON, Canada
[7] Univ Toronto, Dept Family & Community Med, Toronto, ON, Canada
[8] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[9] Univ Toronto, Ctr Vaccine Preventable Dis, Toronto, ON, Canada
[10] Oregon Hlth & Sci Univ, Portland, OR 97201 USA
[11] Univ Toronto, Dept Lab Med & Pathobiol, Toronto, ON, Canada