Health authorities say the risk of COVID-19 patients developing into critical cases is 100 percent lower for those who received a booster shot than for those not getting vaccinated. 

The Korea Disease Control and Prevention Agency(KDCA) said on Thursday that those receiving three and two doses of coronavirus vaccine had 80-point-nine percent and 58-point-two percent lower chance of contracting the virus, respectively, than those who have yet to receive any. 

As for the risk of progressing into serious and critical cases, the comparative figures for those given a third and second doses were lower by 100 percent and 92-point-three percent, respectively, than that for those who have not been inoculated.  

The agency said those aged 60 and older only accounted for 16-point-six percent of the new COVID-19 patients in the first week of this year, falling from 30-point-five percent in the third week of last month. 

Attributing it to a growing vaccination rate for the age group, the agency encouraged the public to get booster shots. Over 82 percent of those aged 60 and older have received booster shots so far.