 The article discusses the use of mass vaccination to combat the COVID-19 pandemic, the approval of several vaccines by the World Health Organization, and the emergence of safety concerns and adverse events that require prompt evaluation, as reported in a case of a healthy woman who developed longitudinally extensive transverse myelitis after being vaccinated with the AstraZeneca vaccine. This article was authored by Saeed Farzad Marufi, Fereshta Nadari Badani, Fate-Marizania, and others.