1 National Institute for Medical Research, Muhimbili Centre, Dar es Salaam, Tanzania; Institute for Global Health, University College London, London, London WC1N 1EH, UK; Alliance for Africa Health and Research, Dar es Salaam, Tanzania; School of Public Health and Social Sciences, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania. Electronic address: gsmfinanga@yahoo.com.
2 National Institute for Medical Research, Muhimbili Centre, Dar es Salaam, Tanzania.
3 School of Public Health and Social Sciences, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.