1. Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA
2. San Mateo County Health Department, San Mateo, CA
3. Infectious Disease Epidemiology Prevention and Control Division, Minnesota Department of Health, St. Paul, MN
4. Bureau of Communicable Disease Control, Massachusetts Department of Public Health, Boston, MA
5. Kaiser Foundation Research Institute, Oakland, CA
6. Harvard Vanguard Medical Associates, Boston, MA
7. HealthPartners Research Foundation, Minneapolis, MN
8. Austin/Travis County Health and Human Services Department, Austin, TX
9. Central Texas Veterans Health Care System, Temple, TX