Affiliation: | 1. Gastroenterology, Department of Medicine, University of Washington, Seattle, Washington, USA;2. Divisions of Allergy & Infectious Disease, Department of Medicine, University of Washington, Seattle, Washington, USA;3. Division of Geriatrics, San Francisco VA Medical Center and University of California, San Francisco, California, USA;4. Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA |