1. From the University of California, San Francisco, San Francisco, Harbor-University of California, Los Angeles, Medical Center, Torrance, and University of California, Berkeley, Berkeley, California; Beth Israel Deaconess Medical Center, Massachusetts Department of Public Health, and The Fenway Institute of Fenway Community Health, Boston, Massachussetts; Centers for Disease Control and Prevention, Atlanta, Georgia; and Brown University and Miriam Hospital, Providence, Rhode Island.