International Rhinologic Society Rhinology 0300-0729 2026 04 02 Critical appraisal of methodological rigor in a systematic review on post-COVID-19 vaccination-associated olfactory dysfunction EN T. Gupta Department of ENT and Head-Neck Surgery, Uttar Pradesh University of Medical Sciences, Saifai, India J.K. Verma Department of ENT and Head-Neck Surgery, Uttar Pradesh University of Medical Sciences, Saifai, India Journal Article 3405 10.4193/Rhin25.440 We read with keen interest the article by Kawabata et al. titled “Olfactory disorder after COVID-19 vaccination,” which explores 16 cases of olfactory dysfunction temporally associated with vaccination. The paper addresses an important and under-recognized topic; however, several methodological aspects warrant clarification to aid accurate interpretation. First, the inclusion of five institutional cases within a review otherwise presented as PRISMA-compliant raises questions regarding methodological consistency. Under PRISMA, all included studies should be identified through transparent and reproducible database searches. Clarifying whether institutional data were processed separately from literature-derived cases would strengthen transparency and avoid confusion about the evidence level.