[1] Univ Calif San Diego, Sch Med, Div Infect Dis, San Diego, CA 92103 USA
[2] Harvard Univ, Brigham & Womens Hosp, Div Infect Dis, Sch Med, Boston, MA 02115 USA
[3] AIDS Clin Trials Grp Community Sci Subcomm, Madison, WI USA
[4] NIH, Div Aids, Bldg 10, Bethesda, MD 20892 USA