The three people are Zhou Shimin, director of Dazhuang Township Hospital, Hou Huafeng, head of Dazhuang Town Health Care and Epidemic Prevention Station, and Zhou Shikai, a health worker who purchased the involved hepatitis A vaccines.

Without official permission, the town epidemic prevention station organized village doctors to vaccinate about 2,500 students in 19 schools in 17 villages on June 16 and 17, according to local police.

Several students reported dizziness, breath difficulties and limb numbness on the morning of June 17.

Local hospitals had received 121 sickened students by Friday, including a six-year-old pupil who died on Thursday.

Private Provider Has Disappeared

The town epidemic-prevention station purchased 1,000 hepatitis A vaccines from a county epidemic prevention center and 3,000 others from a private medicine provider, Zhang Peng, who has disappeared after the accident.

Local police are still hunting for Zhang, and tracking down sources of the vaccines.

The rest of the vaccines have been sealed, and the samples were sent to a state institution for tests.