Health authorities have suspended this year's vaccination program for the seasonal flu after finding a problem in the distribution process. 

The Korea Disease Control and Prevention Agency(KDCA) announced the decision in a statement late Monday, saying it will temporarily halt the program.

The agency reportedly found a problem in temperature control during the distribution process. The affected vaccines are for children and adolescents aged 13 to 18. 

The agency immediately stopped supplying influenza vaccines from related companies and plans to use those that have already been supplied sequentially after thorough quality verification.
 
In order to ensure quality assurance, the agency temporarily suspended vaccinations for all subjects, including pregnant women as well as those aged 18 or under. 

The nation launched free flu shots on September 8, beginning with babies and children aged six months to nine years. Some 19 million people, or around 37 percent of the population, are eligible for the free vaccinations, after eligibility was expanded this year in consideration of the COVID-19 pandemic.