Most countries promote mass immunisation programmes. The varying policy details raise a raft of philosophical issues. I have two broad aims in this paper. First, I hope to begin to remedy a rather curious philosophical neglect of immunisation. With this in mind, I take a broad approach to the topic hoping to introduce rather than settle a range of philosophical issues. My second aim has two aspects: I argue that the states should have pro-immunisation policies, and I advance a view (...) of the subsequent and more specific question as to which sorts of pro-immunisation policies they should prefer. I use the immunisation policies of the United States and New Zealand to frame my discussion of these substantive questions. Immunisation is effectively compulsory in the United States. New Zealand, by contrast, requires evidence not of immunisation but of immunisation status upon school enrolment: New Zealand's policy effectively makes immunisation choice compulsory. I argue that, as between the pro-immunisation policies of the United States and New Zealand, the latter should be preferred. Though the threshold question as to whether states should have pro-immunisation policies should be answered affirmatively, the move to compulsory immunisation cannot be justified. (shrink)