The legal implications of the use of vaccines to promote individual and group immunity constitute a complex pattern of common and statute law interwoven with the ethical code governing medical practice. In the circumstances under discussion, teaching the theory and practice of vaccination to medical students, several roles have to be considered. Firstly there is the recipient, a baby or schoolchild, both with the oversight of a parent or guardian. In some circumstances the recipient may be an adult. Secondly, there is the person advising upon, and administering the vaccine — either the student or the doctor. Lastly, the Authority in whose premises the teaching and vaccination take place plays a significant role. In the wings, waiting to be cued to activity by misfortune, the General Medical Council, the Health Service Commissioner, the Health and Safety Executive, lawyers and community health councillors play a passive, but everpresent role.