1. Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105-27941;
2. Glaxo Wellcome Inc., Research Triangle Park, North Carolina 277092;
3. Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas 770303; and
4. Department of Pediatrics, Children’s Memorial Hospital, Chicago, Illinois 606144