(Yonhap) South Korea said Saturday it has signed a deal with US pharmaceutical giant Pfizer Inc. to import additional Pfizer vaccine doses for 20 million people.

The deal came after South Korean health minister Kwon Deok-cheol held two video conferences with his Pfizer counterpart on April 9 and 23.

"The additional deal would allow South Korea to receive coronavirus vaccines more stably," Kwon said in a news conference at the government complex building in Seoul.

South Korea is set to receive Pfizer vaccine doses for 3.5 million people by the end of June. Additional Pfizer vaccines for 29.5 million people are scheduled to be supplied to South Korea in phases, beginning in July.

The latest deal raised the total number of COVID-19 vaccine doses from the World Health Organization's global vaccine COVAX Facility project and pharmaceutical companies to an amount enough to inoculate 99 million people, an amount that is 2.75 times of the 36 million that is needed to achieve herd immunity here.

The pharmaceutical companies are AstraZeneca, Pfizer, Moderna, Johnson & Johnson's Janssen and Novavax.

South Korean health authorities aim to achieve herd immunity by November. The country started its inoculation campaign in late February. (Yonhap)