[1] Univ Witwatersrand, Ctr Hlth Policy, Sch Publ Hlth, ZA-2050 Johannesburg, South Africa
[2] Ghana Hlth Serv, Navrongo Hlth Res Ctr, Accra, Ghana
[3] Univ Cape Town, Hlth Econ Unit, ZA-7700 Rondebosch, South Africa
[4] Ifakara Hlth Inst, Ifakara, Tanzania
[5] London Sch Hyg & Trop Med, London WC1, England