Health authorities encouraged teenagers to get vaccinated against COVID-19, saying there could be a spike in infections among them.

Senior health ministry official Son Young-rae said on Wednesday that because immunity is low among unvaccinated teens, they are at high risk during the nation’s transition into living with COVID-19.

The official said the infection rate among teenagers was observed to have risen in other countries that already began a similar transition, as he urged young people to seek immunization.

This comes as the number of teenagers who tested positive jumped from 201 on October 25 to 465 on October 30.

While third-year high school students completed vaccination by August ahead of the nationwide university entrance exam on November 18, 12 to 17 year olds became eligible starting in the fourth quarter.

As of Tuesday, 27-point-eight percent of those aged 12 to 15 have made vaccination reservations. Among those aged 16 and 17, 65-point-four percent had reservations.