1. Department of Applied Mathematics, University of Washington , Seattle, WA , USA
2. Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center , Seattle, WA , USA
3. Cancer Control and Population Sciences, Huntsman Cancer Institute , Salt Lake City, UT , USA
4. Department of Family and Preventative Medicine, University of Utah , Salt Lake City, UT , USA
5. Department of Bioethics and Humanities, University of Washington School of Medicine , Seattle, WA , USA