University of Washington School of Medicine, Division of Allergy and Infectious Disease, Seattle
Reprints or correspondence: Dr. Walter E. Stamm, University of Washington, Div. of Allergy and Infectious Disease, HSB BB1225, Box 356523, 1959 NE Pacific St., Seattle, WA 98195-6523 ([email protected]).
Received 7 November 2006; accepted 5 December 2006.
Potential conflicts of interest: none reported
