Health authorities have begun to retrieve some 700-thousand syringes from COVID-19 vaccination sites following reports that foreign substances were found inside LDS, or low dead space syringes, currently used in inoculations.

The Korea Disease Control and Prevention Agency (KDCA) said Saturday that following 21 such reports, the syringe manufacturer, in a preemptive move, has collected 630-thousand of its product by Friday and will collect 70-thousand more by this week.

All of the 700-thousand to be retrieved are made by one manufacturer and 500-thousand of this total have already been used in administering the AstraZeneca vaccine.

However, a Food and Drug Safety Ministry official said that nurses would have seen the foreign substance before giving shots, so compromised vaccinations are not believed to have taken place. 

The official said authorities have inspected the manufacturer and had it fix the problems.