The administering of a second COVID-19 booster shot for those in their 50s begins on Monday.

Health authorities said that the fourth round of COVID-19 vaccinations will begin on Monday for those in the age group who made reservations.

Last month, the authorities expanded eligibility for a second COVID-19 booster shot to those in their 50s amid rising concerns about an upsurge in infections.

People aged 18 and older who have underlying health conditions also became eligible for a fourth shot, along with patients and workers at facilities with populations vulnerable to the virus, such as nursing homes and homeless shelters.

Meanwhile, health authorities will stop the telephone monitoring of high-risk groups among COVID-19 patients recovering at home from Monday in light of increases in face-to-face treatment and the supply of antiviral pills.

The authorities had been monitoring at-home COVID-19 patients aged 60 and older and those with immune disorders by calling them once a day to check their condition. These people will now have to visit respiratory disease treatment facilities like regular patients if they have symptoms.