Evaluation of the early effects of the first-dose administration of the Sinovac vaccine on the retina, choroid, and optic disc using optical coherence tomography (OCT) and OCT-angiography.

Aim: To determine the effects of the first-dose administration of the Sinovac vaccine on the retina, choroid, and optic disc in healthy participants.

Methods: This prospective design study was conducted with 27 healthy healthcare workers who received the first dose of Sinovac vaccine and 25 healthy controls who were not vaccinated. In the vaccinated group, ophthalmological examinations and measurements were performed before vaccination and one week and one month after vaccination. Subfoveal, nasal, and temporal choroidal thicknesses (CTs), retinal nerve fiber layer (RNFL) thickness, and macular thickness (MT) were determined using spectral domain-optical coherence tomography at all visits. Superficial, deep, and peripapillary radial capillary plexus (superficial capillary plexus, deep capillary plexus (DCP), and radial peripapillary capillary, respectively), choriocapillaris vascular density, and foveal avascular zone parameters were measured on optical coherence tomography-angiography (OCT-A).

Results: No significant difference was detected between the two groups in terms of the parameters measured by OCT and OCT-A (p > 0.05 for all). The CT values measured in all quadrants were significantly higher at the first week after vaccination (p < 0.05 for all), and they returned to their pre-vaccination values at the first month post-vaccination measurement (p > 0.05 for all). Concerning the RNFL and MT values, there was no significant difference between the pre-vaccination and post-vaccination first-week measurements (p > 0.05 for all), but a statistically significant increase was detected in the post-vaccination first-month MT and RNFL measurements (p < 0.05 for all). Only the decreases in the foveal DCP and choriocapillaris vascular density values were significant at the first week after vaccination (p < 0.05 for all).

Conclusion: The early changes detected after vaccination in this study suggest the possibility that autoimmune, vascular, and inflammatory diseases may simultaneously emerge in the early post-vaccination period or may be triggered after vaccination, or that the vaccine may unmask these diseases.