[1] Columbia Univ, Sergievsky Ctr, New York, NY 10032 USA
[2] Columbia Univ, Dept Epidemiol, New York, NY 10032 USA
[3] Columbia Univ, Dept Biostat, New York, NY 10032 USA
[4] Columbia Univ, Mailman Sch Publ Hlth, New York, NY 10032 USA
[5] Boston Univ, Sch Med, Ctr Int Hlth & Dev, Boston, MA 02215 USA
[6] Univ Alabama Birmingham, Sch Publ Hlth, Dept Epidemiol, Birmingham, AL USA
[7] Univ So Calif, Dept Pediat, Los Angeles, CA USA
[8] Univ Zambia, Univ Teaching Hosp, Lusaka, Zambia
[9] Lusaka Dist Hlth Management Team, Lusaka, Zambia