Holland, MaryZachary, Chase E.2014-11-212014-11-212014-11-2093 OR. L. REV. 10196-2043https://hdl.handle.net/1794/1859248 pagesThis Article explores both the theory and practice of herd immunity. The authors evaluate the scientific assumptions underlying the theory, how the theory applies in law, a game theory approach to herd immunity, and a possible framework for rational policymaking. The Article argues that herd immunity is unattainable for most diseases and is therefore an irrational goal. Instead, the authors conclude that herd effect is attainable and that a voluntary vaccination marketplace, not command-and-control compulsion, would most efficiently achieve that goal.en-USAll Rights Reserved.Article