South Korea has confirmed a total of 29 so-called breakthrough COVID-19 infections so far, with 28 of them inoculated in the country, health authorities said Friday.

The Korea Disease Control and Prevention Agency (KDCA) said the patients have tested positive for COVID-19 as of Monday even after being administered with the full-dose vaccine regimen here.

A "breakthrough case" is when a person tests positive for COVID-19 between the first and second doses of a two-dose regimen or a person tests positive after full vaccination.

The KDCA said similar cases may increase as the country's vaccine rollout revs up, though the rate of breakthrough cases per total is extremely low.

The authorities said even after full vaccinations, a person can be infected with COVID-19. They also said that those who are classified as breakthrough infection cases have mild symptoms or are asymptomatic.

As of Friday, a total of more than 14.23 million people have received their first shots of COVID-19 vaccines since the vaccine rollout on Feb. 26, taking up 27.7 percent of the total 51.3 million population, the KDCA said. (Yonhap)