Retinal Vein Occlusion Amongst People Vaccinated by mRNA- and Viral Vector- COVID-19 Vaccines: A Systematic Review.

Vaccines are highly effective in lowering the mortality due to COVID-19. Although several suspected adverse events or side effects after vaccination including retinal vein occlusion (RVO) have been reported. We conducted a systematic review using PRISMA methods to analyze the occurrence of RVO among people vaccinated by COVID-19 mRNA- vs viral vector- vaccines on 4 databases from 1-1-2021 to 31-12-2022 using specified MeSH terms. All included studies were assessed using JBI critical appraisal tools for eligibility. The final included studies are 31 studies (n=78 cases from 75 patients; 3 of these patients suffered twice). The median age of the patients was 61 years (28 to 96 years old) and most of them were female (52.00%). Thirty-nine patients received the mRNA vaccine (52.00%), while 36 patients received the viral vector vaccine (48.00%) before the event. The RVO diagnoses are based on physical examination confirmed by Fluorescein Angiography (FA), and/or Optical Coherence Tomography (OCT). The median time interval between vaccination and RVO was 6 days in the mRNA vaccine group and 4 days in the viral vector vaccine group. Central retinal vein occlusion (CRVO) and Branch Retinal Vein Occlusion (BRVO) were tied as the most common diagnosis in the mRNA vaccine group (20.51% and 20.51%), whilst in the viral vector vaccine group CRVO was the most common diagnosis (17.94%). Most of these cases had good outcomes with improved visual impairment in one or both eyes. From this review, we could not ascertain that the RVO occurs due to the type of COVID-19 vaccines because of the detailed data on the dosage and the history of illness of each patient. However, the awareness that the RVO could develop after COVID-19 vaccination must be taken into consideration, even though it is rare.