More than 1,300 South Koreans have received potentially defective flu vaccines, health authorities said Wednesday.
The Korea Disease Control and Prevention Agency said a total of 1,362 people were found to have been injected with the vaccines that were not supposed to be administered after being exposed to room temperature.
The figure marked a hike of 489 from Tuesday, according to South Korean News Agency (Yonhap).
Meanwhile, 122 patients in nursing homes in the western port of Incheon received flu vaccines that were not exposed to room temperature.
Among them, three female patients in their 80s and 90s died in recent days after receiving the flu shots, but the public health agency said the causes of deaths were their worsened underlying health conditions.
None of the other patients injected with normal vaccines in the nursing home have showed abnormal reactions, the agency said.
Inactivated vaccines should be stored in refrigerators, and exposure to room temperatures could result in decreased vaccine potency and increased risk of vaccine-preventable diseases.
But the safety of those vaccines exposed to room temperatures has yet to be determined.
An ongoing study on the safety of the exposed vaccines is expected to wrap up early next week.