Necessity and least infringement conditions in public health ethics.

The influential public health ethics framework proposed by Childress et al. includes five "justificatory conditions," two of which are "necessity" and "least infringement." While the framework points to important moral values, we argue it is redundant for it to list both necessity and least infringement because they are logically equivalent. However, it is ambiguous whether Childress et al. would endorse this view, or hold the two conditions distinct. This ambiguity has resulted in confusion in public health ethics discussions citing the Childress et al. framework, as demonstrated by debate between Resnik and Wilson and Dawson. We analyse this debate to resolve these ambiguities. Finally, we argue that the necessity/least infringement principle of the Childress et al. framework applies only in cases in which only one intervention is to be implemented to achieve one specific goal. In other cases, it is not essential to require that only the least infringing intervention be implemented.