Although there has been unprecedented attention to inoculation theory in recent years, the potential of this research has yet to be reached. Inoculation theory explains how immunity to counter‐attitudinal messages is conferred by preemptively exposing people to weakened doses of challenging information. The theory has been applied in a number of contexts (e.g., politics, health) in its 50+ year history. Importantly, one of the newest contexts for inoculation theory is work in the area of contested science, misinformation, and conspiracy theories. Recent research has revealed that when a desirable position on a scientific issue (e.g., climate change) exists, conventional preemptive (prophylactic) inoculation can help to protect it from misinformation, and that even when people have undesirable positions, “therapeutic” inoculation messages can have positive effects. We call for further research to explain and predict the efficacy of inoculation theory in this new context to help inform better public understandings of issues such as climate change, genetically modified organisms, vaccine hesitancy, and other contested science beliefs such as conspiracy theories about COVID‐19.

Inoculation theory, a theory of conferring resistance to persuasive influence, has established efficacy as a messaging strategy in the health domain. In fact, the earliest research on the theory in the 1960s involved health issues to build empirical support for tenets in the inoculation framework. Over the ensuing decades, scholars have further examined the effectiveness of inoculation-based messages at creating robust positive health attitudes. We overview these efforts, highlight the structure of typical inoculation-based health messages, and describe the similarities and differences between this method of counter-persuasion and other preparatory techniques commonly employed by health researchers and practitioners. Finally, we consider contexts in which inoculation-oriented health messages could be most useful, and describe how the health domain could offer a useful scaffold to study conceptual issues of the theory.

One of the most significant departures from conventional inoculation theory is its intentional application for individuals already “infected”—that is, inoculation not as a preemptive strategy to protect existing positions from future challenges, but instead, inoculation as a means to change a position (e.g., from negative to positive) and to protect the changed position against future challenges. The issue is important for persuasion scholarship in general, as theoretical boundary conditions help at each stage of persuasion research development, serving as a guide for literature review, analysis, synthesis, research design, interpretation, theory building, and so on. It is an important issue for inoculation theory and resistance to influence research, specifically, for it gets at the very heart—and name and foundation—of inoculation theory. This article offers a theoretical analysis of inoculation theory used as both prophylactic and therapeutic interventions and concludes with a set of recommendations for inoculation theory scholarship moving forward.

Threat plays a pivotal role in many theoretical explanations for how inoculation confers resistance, but some empirical data raise questions about threat's role in inoculation. Our study explores some of the unresolved dimensions of threat in inoculation theory. Results indicate that an explicit forewarning included in an inoculation treatment message generates threat, as does the presence of counterarguments and their refutations. Follow-up tests suggest that the forewarning component may be most responsible for generated threat in inoculation, and that a prompt to consider experienced threat may lead to enhanced resistance to subsequent attack messages.