[1] STATENS SERUM INST,DEPT INFECT IMMUNOL,DIV BIOTECHNOL,DK-2300 COPENHAGEN,DENMARK
[2] STATENS SERUM INST,DEPT BIOSTAT,DK-2300 COPENHAGEN,DENMARK
[3] UNIV LONDON LONDON SCH HYG & TROP MED,TROP HLTH EPIDEMIOL UNIT,LONDON WC1E 7HT,ENGLAND
[4] MRC LABS,BANJUL,SENEGAMBIA
[5] KAROLINSKA INST,NOVUM,CTR BIOTECHNOL,S-14186 HUDDINGE,SWEDEN