Japan began administering COVID-19 booster shots to health care workers nationwide on Wednesday as the country braces for the potential impact of the omicron variant, a concerning new strain of the coronavirus that scientists worldwide are scrambling to research.

Five doctors and 13 nurses at the state-run Tokyo Medical Center in Meguro Ward received their third jabs Wednesday morning. The hospital’s director, Kazuhiro Araki, who got the shot, said he feels relieved that the rollout began as scheduled.

Medical personnel at Tokyo Medical University's Hachioji Medical Center and some hospitals in Aichi and Saitama prefectures, among other facilities, also received their third shots.