Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fariview Ave N, Seattle, WA 98109, USA. gfinak@fhcrc.org|Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fariview Ave N, Seattle, WA 98109, USA. gfinak@fhcrc.org|Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fariview Ave N, Seattle, WA 98109, USA. gfinak@fhcrc.org|Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fariview Ave N, Seattle, WA 98109, USA. gfinak@fhcrc.org