A patient being treated for blood clots after receiving the AstraZeneca COVID-19 vaccine died Wednesday.

The Korea Disease Control and Prevention Agency(KDCA) told reporters that the man in his early 30s died on Wednesday afternoon. He was previously confirmed as the nation’s second clotting case among AstraZeneca recipients. 

He received the vaccine on May 27 and showed symptoms of a severe headache and nausea after nine days. He was later admitted to a hospital and diagnosed with TTS last Tuesday. 

TTS(thrombosis with thrombocytopenia syndrome) is a very rare but serious side effect of the vaccine where a patient develops blood clots along with low platelet levels. 

The KDCA said the man had no underlying diseases and his direct cause of death was a brain hemorrhage caused by TTS. He is effectively the country's first patient to die from side effects of a COVID-19 vaccine.