Health care institutions have paid increasing attention to preventing nosocomial transmission of influenza through vaccination of health care personnel. While multifaceted voluntary interventions have increased vaccination rates, proponents of mandatory programs contend the rates remain unacceptably low. Conventional bioethical analyses of mandatory programs are inadequate; they fail to account for the obligations of nonprofessional personnel or to justify the weights assigned to different ethical principles. Using an ethics framework for public health permits a fuller analysis. The framework's focus on fairness accentuates the potential differences between the risk of transmitting infection and employment status, and the need to equitably evaluate exemptions. The framework's emphasis on balancing benefits and burdens highlights the need to justify a specific goal and questions the need to exclude all nonmedical exemptions. While mandatory vaccination programs are justifiable, greater attention should be paid to their implementation.