1. Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle
2. Division of Allergy and Infectious Diseases, University of Washington, Seattle
3. Division of Infectious Diseases, Oregon Health and Science University, Oregon
4. Epidemiology Programs, Oregon Health and Science University–Portland State University School of Public Health, Oregon
5. University of Iowa Carver College of Medicine, Iowa City
6. Emerging Infections Network, San Francisco
7. Division of Infectious Diseases, San Francisco General Hospital, University of California, San Francisco