SEOUL: South Korea injected 857,000 COVID-19 vaccine doses on Monday, setting a daily record in its inoculation drive that took its vaccination rate to 16.4% for a first dose, data from the Korea Disease Control and Prevention Agency (KDCA) showed.

Hitherto, a slow vaccine rollout due to global shortages and shipment delays had complicated South Korea's efforts to subdue latest wave of infections, after the country won plaudits last year for using aggressive and high-tech contact tracing to quickly tamp down on outbreaks.

But with the inoculation drive ramping up, South Korea said last week that it expects to meet its vaccination target for the first half of the year by inoculating up to 14 million people ahead of schedule.

The government plans to vaccinate 70% of its 52 million population by the third quarter, starting with kindergarten and primary school teachers during summer break, with the aim of achieving herd immunity before November.

South Korea reported 454 new confirmed coronavirus cases on Monday, bringing the total tally to 145,091 infections, with 1,975 deaths.

Half of the new cases were fuelled by gatherings of family and friends, government figures showed.

Daily new infections have held stubbornly in a range of 400 to 700 for the past few weeks, making the government pull back from plans to relax social distancing rules.

Everyday interactions with family, friends and co-workers at home and workplaces were among the major risks of transmission, as were night spots and karaoke bars, the KDCA said.

Authorities on Monday advised the public to take two shorter vacations instead of a long one and encouraged private and public companies to stagger holidays for employees and extend the holiday season to prevent crowding at tourist destinations.