In December 2019, a novel coronavirus, SARS-CoV-2, first reported in the Wuhan city of China, soon spread around the world and caused substantial impact on health. As of March 2022, SARS-CoV-2 has infected ~400 million people worldwide and caused 6.07 million deaths. During the global COVID-19 pandemic, people in Taiwan maintained normal lives due to longstanding strategies of masking, personal hygiene, social distancing, quarantine measures and contact tracing. Unfortunately, the community outbreak of COVID-19 in Taiwan began in May 2021. To stop virus transmission, Taiwan Centers for Disease Control made an effort to increase COVID-19 vaccination coverage. Four types of vaccines, including Moderna, AstraZeneca (AZ), Pfizer-Biontech (BNT) and MVC COVID-19Vaccine, are available in Taiwan. Headache is the most common neurological side effect after COVID-19 vaccination. In phase 3 clinical trials, the incidence of headache was 24%-35% and 46%-63% after first and second doses of Moderna vaccination; 1 50.2% after first and second doses of AZ vaccination; 2 and 25%-42% and 39%-52% after first and second doses of BNT vaccination. 3 In s phase 2 clinical trial, the incidence of headache was 15.1% and 13.2% after first and second doses of MVC COVID-19 vaccination, respectively. 4 However, some rare neurological disorders post-COVID-19 vaccine, like Bell's palsy, encephalomyelitis, Guillain-Barré syndrome, and transverse myelitis have been reported. [5][6][7][8] Here, we report a case of new-onset acute encephalomyelitis after receiving the first dose of AZ vaccine.A 55-year-old man was admitted to hospital with fever and consciousness disturbance. The patient received the first dose of AZ vaccine 1 week before admission. Mild injection site pain was observed and subsided in the following 2 days. Two days before admission, the patient suffered from fever up to 39°C, nonproductive cough, general malaise and muscle soreness. One day before admission, progressive weakness and lowered consciousness and drowsiness developed. He had difficulty in sitting up from bed and changing clothes due to weakness. Due to progressive disorientation to people and place and slow response, he was referred to our hospital for help.