1. Division of Epidemiology and Prevention, Institute of Human Virology, University of Maryland, Baltimore, Maryland.
2. University of Illinois at Chicago, College of Medicine and School of Public Health, Chicago, Illinois.
3. Brigham & Women's Hospital, Boston, Massachusetts.
4. University of Puerto Rico, San Juan, Puerto Rico.
5. National Institute of Child Health and Human Development, Bethesda, Maryland.
6. Baylor College of Medicine, Houston, Texas.
7. State University of New York, Brooklyn, New York
8. Division of AIDS, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland.
9. Investigators and institutions in the Women and Infants Transmission Study are listed in the Appendix.