From Thursday, those aged 60 and older will be able to receive a second booster shot against COVID-19.

The COVID-19 vaccine response team announced the fourth vaccine for the age group on Wednesday as part of its effort to prevent additional virus-related critical cases and deaths.

Those eligible can get their fourth dose 120 days after their third shot, which will be administered with mRNA vaccines as a standard, such as Pfizer or Moderna. If desired, the protein subunit vaccine Novavax can also be requested.

The decision was made as the effectiveness of the first booster shot has been waning over time, and COVID-19 infections for those over the age of 60 accounted for more than 20 percent of the total in the first week of April.