An effective correction on COVID-19 misinformation is necessary for improving public health. To explore the effects of various methods to correct misinformation on social media, we examined the effects of accumulated corrections (e.g., one vs. two. vs. three) by two types of social-media users (e.g., individuals vs. health organizations) on COVID-19 fake news. We found that participants tended to reduce their perceived accuracy ratings and willingness to share misinformation with correction compared to a control condition. However, a significant effect of accumulated corrections was not observed. To understand the possible reasons behind the ineffectiveness, we did an exploratory analysis on expressional types of correcting comments and found that the simpler the comment is, the more effective the correction is. Our findings suggest making correcting comments “simple” in terms of COVID-19 fake news on social media.