The South Korean government stated that about 760,000 South Koreans who have received a first dose of British pharmaceutical company AstraZeneca Plc's (LON:AZN) COVID-19 vaccine will be offered US pharmaceutical company Pfizer Inc's (NYSE:PFE) vaccine as a second shot, Reuters news agency reported on Friday.

This is due to shipment delays by global vaccine sharing scheme COVAX.

This shipment has been delayed to July 2021 or later, while the country had used up available AstraZeneca reserves to meet stronger than expected participation in its vaccination campaign.

According to Korea Disease Control and Prevention Agency (KDCA), South Korea has so far run a clinical trial, that mixes COVID-19 doses from AstraZeneca with those from Pfizer and others, in 100 health workers to examine the formation of antibody and other immune effects.

Several countries, including Canada and Spain, have already approved such dose-mixing mainly due to concerns about rare and potentially fatal blood clots linked to the AstraZeneca vaccine.

As on 17 June 2021, over 27% of South Korea's 52 million population have been inoculated with at least one dose of a COVID-19 vaccine .

The country is reportedly on track to meet a target of 70% by September and reach herd immunity before November 2021.