[1] Fac Med Necker Enfants Malad, Inst Necker, F-75015 Paris, France
[2] MRC S Africa, Congella, South Africa
[3] Yale Univ, Sch Med, New Haven, CT 06520 USA
[4] Johns Hopkins Univ, Baltimore, MD USA
[5] Univ Calif San Diego, San Diego, CA 92103 USA
[6] Ist Super Sanita, Int AIDS Soc, I-00161 Rome, Italy
[7] Makerere Univ, Inst Publ Hlth, Kampala, Uganda
[8] Inst Pasteur, Paris, France
[9] UCL, London WC1E 6BT, England