Some 250-thousand doses of the COVID-19 vaccine developed by Pfizer and BioNtech have arrived in South Korea on Wednesday, one week after the first shipment entered the country.

The second shipment of doses for some 13 million people the government directly secured with Pfizer will be used to inoculate elderly citizens aged 75 or older, as well as people who live or work in senior facilities starting from Thursday.

Meanwhile, the government is mulling various ways to smoothly carry out its vaccination program in the second quarter amid an unstable supply of vaccines around the world.

While continuously working to secure additional doses, authorities are said to be considering extending the interval between the first and second doses of the AstraZeneca vaccines currently being supplied to 12 weeks from the current ten weeks.