Ethical considerations from both the clinical and public health perspectives have been used to examine whether it is ethically permissible to mandate the seasonal influenza vaccine for healthcare workers (HCWs). Both frameworks have resulted in arguments for and against the requirement. Neither perspective resolves the question fully. By adding components of justice to the argument, I seek to provide a more fulsome ethical defence for requiring seasonal influenza immunisation for HCWs. Two critical components of a just society support requiring vaccination: fairness of opportunity and the obligation to follow democratically formulated rules. The fairness of opportunity is informed by Rawls' two principles of justice. The obligation to follow democratically formulated rules allows us to focus simultaneously on freedom, plurality and solidarity. Justice requires equitable participation in and benefit from cooperative schemes to gain or profit socially as individuals and as a community. And to be just, HCW immunisation exemptions should be limited to medical contraindications only. In addition to the HCWs fiduciary duty to do what is best for the patient and the public health duty to protect the community with effective and minimally intrusive interventions, HCWs are members of a just society in which all members have an obligation to participate equitably in order to partake in the benefits of membership.