It added that it had secured a total 192 million doses of vaccines, including those from Moderna Inc, AstraZeneca PLC, Johnson & Johnson's and Novavax.
"The government has acquired COVID-19 vaccines large enough to vaccinate approximately 100 million people...(which) is double the entire population of South Korea," Health Minister Kwon Deok-cheol told a briefing.
There were no cases of severe illness or deaths among those who got the vaccine, the company said.
The vaccine was 86% effective in protecting against the more contagious virus variant first discovered and now prevalent in the United Kingdom, for a combined 90% effectiveness rate overall based on data from infections of both versions of the coronavirus.
In an analysis of current supply deals for COVID-19 vaccines, the ONE Campaign said wealthy countries, such as the United States and Britain, should share the excess doses to “supercharge” a fully global response to the pandemic.
On Thursday, the World Health Organization urged nations with vaccines not to share them unilaterally, but to donate them to the global COVAX scheme to ensure fairness.