ChAdOx1 nCoV-19 (AZD1222) is a replication-deficient chimpanzee adenovirus vectored vaccine developed by Oxford and AstraZeneca for a disease we all know as Coronavirus, or COVID-19. Ongoing clinical studies reveal that the ChAdOx1 nCoV-19 vaccine has a tolerable safety profile and is effective against symptomatic COVID-19. This vaccine may prove crucial in boosting herd immunity, averting life threatening illness, and relieving the current pandemic. In this mini review, we performed a thorough literature search through PubMed and Google Scholar and reported various case reports associated with complications of the adenovirus-vectored COVID-19 vaccine. Various adverse effects of the ChAdOx1 nCoV-19 vaccine were reported around the globe, which were often serious but rare and developed into life-threatening pathologies such as GBS, thrombocytopenia, demyelinating neuropathies, progressive dementia, cerebral infarction, IgA vasculitis, hemophagocytic lymphohistiocytosis, herpes zoster, cutaneous reactions, and vein thrombosis. These worldwide reported complications, which are usually rare and severe, will aid clinicians in understanding and managing unforeseen situations. There is a need for more research to find out more about these complications and their etiopathogenesis. However, the benefits of these vaccinations for stopping the spread of the outbreak and lowering the fatality rate outweigh the potential risk of the uncommon complications.