1. University of Sheffield Sheffield Centre for Health and Related Research, , 30 Regent St, Sheffield City Centre, Sheffield S1 4DA , UK
2. University of Ibadan Department of Biomedical Laboratory Science, , Nigeria, Box 4078, University of Ibadan Post, Ibadan 200001, Oyo State , Nigeria
3. University of Cape Town Department of Medicine, College of Medicine, , School of Public Health Barnard Fuller Building, Anzio Rd, Observatory, Cape Town 7935 , South Africa
4. Kenyatta University Department of Health Science, , School of Health Sciences Off Thika Rd, 43844-00100 GPO, Nairobi , Kenya
5. Ghana College of Physicians and Surgeons1 Jomo Kenyatta Roade , Ridge, Accra, P. O. Box MB 429, Accra , Ghana