Vaccinations for people aged 17 to 49 will start Monday, as South Korea struggles to clamp down a fourth wave of the coronavirus.

The upcoming vaccine roll out will be crucial in the country’s plan to reach herd immunity by November, the Korea Disease Control and Prevention Agency said, as it covers over 16 million people considered the most socially active among all age groups.

Eligible are those born after Jan. 1, 1972, and before Dec. 31, 2003, a group that includes some 17-year-olds. They can reserve COVID-19 vaccination appointments through the government website starting Monday at 8 p.m. Reservations will run until Aug. 21.

To prevent the booking system from crashing, the authorities have introduced a 10-day rotation, in which people can reserve jabs on only designated days based on the last digit of their birth date.

People whose birth date ends with a 9 will be able to book Monday, which is Aug. 9, while those with a 0 will get to reserve the next day.

The government will open additional reservation opportunities for people who miss their date.

Those aged 36 to 49 can make reservations from 8 p.m. Aug. 19 to 6 p.m. Aug. 20. Those 35 and younger can apply for vaccines starting on 8 p.m. Aug. 20 to 6 p.m. of Aug. 21.

Due to the volume of vaccines expected to be rolled out this time, the government has expanded methods of identification to include simple identification certificates issued by Kakao, Naver and PASS. The KDCA recommends people who want to use these methods to have them ready at least a day in advance.

Reservations made by a proxy or using multiple devices will be strictly prohibited.

The number of people trying to reserve at any one time will be visually represented through colors. Green means “smooth,” yellow means “delays,” red means “busy” and gray means “unavailable.”

The KDCA says the reservation system can handle a daily cap of 1.9 million people and said it expects reservations to go through within 30 to 50 minutes.

“We recommend people avoid making reservations on 8 p.m. when traffic is expected to reach its peak,” said an official from the KDCA. “After 9 p.m., reservations are expected to go through smoothly.”

Inoculations will start from Aug. 26 and run until Sept. 30. Patients will be given either the Pfizer or Moderna vaccine.

Businesses are recommended to provide inoculated individuals with a one-day COVID-19 vaccine vacation.