On June 2, the Central Epidemic Command Center (CECC) pointed out that the Advisory Committee on Immunization Practices (ACIP) of the Ministry of Health and Welfare had held an expert meeting on May 31 and confirmed the first case of thrombosis with thrombocytopenia syndrome (TTS) following the AstraZeneca vaccine shot in Taiwan. The person developing TTS was alert to the clinical symptoms and received treatment in time; the symptoms have improved, and the person has been moved to a general ward for further observation.

As of now, a total 461,647 people have been vaccinated with the AstraZeneca vaccine. As this case of TTS is the first one in Taiwan, the incidence rate is 2.1 per million. In other countries, such as the UK, the rate of developing TTS following the first dose of the vaccine is approximately 12.3 per million (as of May 1); in the EU, the rate is 6.5 per million (as of April 4). The ACIP recommends that the CECC should continue to monitor adverse reactions after inoculations.

The CECC urges members of the public to seek immediate medical care if they experience any of the following symptoms within 28 days after vaccination: severe and persistent headache, changes in vision, epilepsy, severe abdominal pain lasting for more than 24 hours, severe chest pain or breathing difficulties, swelling or pain in legs, spontaneous blood spots under the skin beyond the injection site, bruising or purpura. When seeking medical attention, members of the public are urged to inform the doctor of vaccination history to facilitate diagnosis of cause of illness and clinical treatment.