[1] Newcastle Univ, Inst Ageing & Hlth, Newcastle Upon Tyne, Tyne & Wear, England
[2] Kilimanjaro Christian Med Univ Coll, Dept Microbiol & Immunol, Moshi, Tanzania
[3] Kilimanjaro Christian Med Ctr, Kilimanjaro Clin Res Inst, Dept Res, Moshi, Tanzania
[4] Kilimanjaro Christian Med Univ Coll, Dept Internal Med, Moshi, Tanzania
[5] Kilimanjaro Christian Med Univ Coll, Dept Hlth Management Syst, Moshi, Tanzania
[6] Kilimanjaro Christian Med Univ Coll, Dept Paediat & Child Hlth, Moshi, Tanzania
[7] Univ Glasgow, Inst Hlth & Wellbeing, Hlth Econ & Hlth Technol Assessment, Glasgow, Lanark, Scotland