How Comment Exposure Affects the Effectiveness of COVID-19 Misinformation Corrections in Countering Misbeliefs on Social Media: The Role of Message Credibility and Issue Involvement

User comments following corrective messages constitute a vital part of the information ecosystem for combating COVID-19 misinformation on social media. Clarifying how they influence correction effectiveness - specifically, their ability to reduce misinformation-driven beliefs - is crucial for optimizing digital communication strategies. Drawing upon the Modality-Agency-Interactivity-Navigability (MAIN) model, this study investigates the main and interactive effects of three comment features - valence (supportive vs. negative), argumentation (subjective vs. argumentative), and tone (civil vs. uncivil) - on correction outcomes. A 2 × 2 × 2 between-subjects experiment (N = 563) tested these relationships, with message credibility as a mediator and issue involvement as a moderator. The results show that comment exposure significantly weakens correction effectiveness. Comment argumentation exerts a robust main effect, with argumentative comments being less detrimental than subjective ones. The interplay of comment valence and tone further modulates this impact. Furthermore, issue involvement moderates the influence of comment valence, with highly involved participants exhibiting stronger resistance to corrections when exposed to negative comments. No mediating role of message credibility is observed. The theoretical and practical implications of these results are discussed.