The interval between Moderna vaccine doses has been dropped from five to six weeks to four weeks.

Health authorities said Friday that people who have received Moderna for their first dose will be able to push up their second dose to four weeks starting Saturday.

Noting the sufficient supply of Moderna vaccines, the state vaccine task force has urged people wanting to get their second jabs at an earlier date to make the change.

Separately, second shots are also possible through same-day reservations of surplus or no-show vaccines using the Kakao or Naver apps.

Authorities said if second shots are administered faster, it can help stem the delta variant's spread and quickly achieve the goal of fully vaccinating 70 percent of the population.