[1] Crucell Holland BV, Leiden, Netherlands
[2] Univ Amsterdam, Acad Med Ctr, Dept Clin Epidemiol & Biostat, NL-1012 WX Amsterdam, Netherlands
[3] Univ Amsterdam, Acad Med Ctr, Dept Human Retrovirol, NL-1012 WX Amsterdam, Netherlands
[4] Univ Amsterdam, Acad Med Ctr, Ctr Poverty Related Communicable Dis, NL-1012 WX Amsterdam, Netherlands