We would like to share ideas on the publication “Multiple cranial nerve palsies following COVID-19 vaccination-Case report”.1 Manea et al.1 concluded that “the most probable etiology of the patient's multiple cranial neuropathy is …..COVID-19 vaccine neurological complications.” The neurological adverse effect of COVID-19 vaccination is possible. However, the exact pathogenesis is unclear. According to a recent report, cranial nerve palsy following COVID-19 vaccination is usually mild and the incidence is not more than that of influenza vaccination.2 In the present case, there are no positive data on inflammation or abnormal antibody-inducing neurological problems. Whether the problem is a coincidence is the main question. Another possible underlying pathogenesis is the hyperviscosity problem induced by COVID-19 vaccination. COVID-19 vaccination might cause increased blood viscosity,3 and excessive high blood viscosity is a possible uncommon cause of cranial nerve palsies.4