This article examines one of the most important claims related to state liability in a health crisis, namely the case of damage caused by the Covid-19 vaccine and the conflict between the judgments rendered by the court of first-instance and the appellate court. The main issue is determining the limits of state liability in the mass vaccination program; where the court of first-instance, relying upon the no harm rule, the right to health, and fair distribution of risk, held the state liable for damages, but the appellate court, emphasizing the fact that the act of vaccination is of a sovereign nature and the limitations of Article 20 of the Islamic Penal Code, upheld the state’s immunity and denied liability. The research methodology is based on a detailed analysis of two judgments, an analysis of Iranian legal foundations (including the Civil Liability Law, the jurisprudential rules of liability, and the principles of the Constitution), and a comparative study of three foreign models (the United States, Europe, and Japan).This comparison demonstrates that the world today uses a model of immunity alongside compensation instead of absolute immunity, and national compensation funds or specialized administrative mechanisms are considered an integral part of vaccination policy.The main finding of the research is that the course of judicial reasoning in this case moved from the state's liability in the judgment rendered by the court of first instance to the state's immunity in the appellate court, and this transition is inconsistent with jurisprudential basis and the principles of restorative justice, as well as valid comparative models; since immunity without compensation has not been accepted in any advanced legal system. On this basis, this research suggests that in order to resolve the inconsistency and duality in the way courts argue and make decisions in such cases, and to insure effective protection of citizens, establishment of a national vaccine compensation fund, enactment of clear criteria for establishing causation in vaccination claims, and drafting special judicial guidelines for cases involving public health crises should be put on the agenda.Furthermore, the research proves that within the framework of the Iranian legal system, the way to overcome the conflict between the responsibility and immunity of the state in the field of vaccination is possible neither by expanding judicial liability based on fault nor by accepting absolute immunity, but by identifying the model of "responsibility for compensation of damage based on social risk" and institutionalizing administrative mechanisms for compensation; a model that is more consistent with the jurisprudential foundations of liability, principles of the Constitution, and valid comparative experiences.