[1] Statens Serum Inst, Bandim Hlth Project, DK-2300 Copenhagen S, Denmark
[2] Rigshosp, Paediat Clin, DK-2100 Copenhagen, Denmark
[3] Bandim Hlth Project, Bissau, Guinea Bissau
[4] Childrens Hosp, Denver & Hlth Sci Ctr, Univ Colorado Sch, Dept Pediat, Denver, CO 80218 USA