[1] Leeds Teaching Hosp NHS Trust, Dept Resp Med, Leeds, England
[2] Queen Mary Univ London, Wolfson Inst Populat Hlth, Ctr Evaluat & Methods, London, England
[3] Univ Manchester, Fac Biol Med & Hlth, Div Immunol Immun Infect & Resp Med, Manchester, England
[4] Univ Leeds, Leeds Inst Hlth Sci, Leeds, England
[5] Queen Mary Univ London, Wolfson Inst Populat Hlth, Ctr Prevent Detect & Diag, London, England
[6] Leeds Teaching Hosp NHS Trust, Dept Res & Innovat, Leeds, England