1. Department of SurgeryJohns Hopkins School of Medicine, Baltimore, MD, USA
2. School of Public HealthUniversity of Witwatersrand, Johannesburg, South Africa
3. International Injury Research UnitBloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
4. School of Public HealthUniversity of Witwatersrand, PRICELESS SA, MRC/Wits Rural Public Health and Health Transitions Research Unit, Johannesburg, South Africa