Yohei Hashimoto1, Masao Iwagami2, Hayato Yamana3, Sachiko Ono4, Yoshinori Takeuchi5, Nobuaki Michihata6, Kohei Uemura7, Makoto Aihara8, Hideo Yasunaga9

Purpose: Case reports have shown ocular adverse events after influenza vaccination. Thus, we investigated the risk of ocular adverse events after influenza vaccination.
Method: This self-controlled case series study used a claims database linked with vaccination records in a large city in Japan between April 2014 and September 2021. Individuals aged ≥65 years who developed ocular adverse events during their follow-up periods were included. We defined the exposure as influenza vaccination and the primary outcome as at least one of the following five eye diseases: uveitis, scleritis, retinal vein occlusion, retinal artery occlusion or optic neuritis. We used conditional Poisson regression to estimate the within-subject incidence rate ratio of ocular adverse events during the risk periods (0–35 days after the vaccination) compared to the control periods.
Results: A total of 4,527 cases were eligible (median age 74 years; male 42%). The incidence rate ratio during the risk period was 1.00 (95% confidence interval 0.86–1.17). No increased risk was observed for individual components of the outcome either; the incidence rate ratio was 1.05 (0.86–1.30) for uveitis, 1.01 (0.70–1.46) for scleritis, 0.92 (0.68–1.24) for retinal vein occlusion, 0.76 (0.31–1.87) for retinal artery occlusion and 0.65 (0.27–1.58) for optic neuritis.
Conclusion: The present self-controlled case series study showed no apparent increase in the risk of ocular adverse events after influenza vaccination in older adults. These results would mitigate concerns of older adults who may hesitate to receive influenza vaccination for fear of ocular adverse events.