1. Chiron Diagnostics, Emeryville, California1;
2. Section of Pediatric and Maternal HIV-1 Infections, Division of Infectious Diseases, Children’s Memorial Hospital,2 and
3. Department of Pediatrics3 and
4. Department of Microbiology and Immunology,4 Northwestern University Medical School, Chicago, Illinois; and
5. Division of Infectious Diseases, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada5