South Korea's health authorites are on alert over a rising number of cases of COVID-19 variants, specifically the one from South Africa.
"In the case of the UK variant, current vaccines and treatments are still effective. But for the South Africa variant, vaccines and treatments are less effective, so we are trying to stop the spread of these mutations."
The UK strain, which is known to be 1.7 times more infectious, is especially prevalent in the southeastern port city of Ulsan.
A total of 76 cases have been reported so far in the Ulsan area in 12 different clusters.
Overall on Thursday, South Korea reported 5-hundred 74 new cases, a decline from the day before, likely because fewer tests were done Wednesday due to Children's Day.
Twelve of those were from overseas.
The country's total number of cases to date has risen to more than 125-thousand.
In the southwestern city of Gwangju, 13 high school students tested positive, so more than a thousand people at their school are being urged to get tested.
Over the past week, nationwide, untraceable cases accounted for 27.6 percent.
Meanwhile, the authorities are looking at approving the Pfizer vaccine for people as young as 12, which several other countries have done recently.
They will make a final decision soon after reviewing the results of clinical trials.
Choi Won-jong, Arirang News.