South Korea reported a record of more than 600,000 coronavirus cases Thursday, with authorities saying the country was near the peak of an Omicron-fuelled infection wave.
According to WHO data, South Korea leads the world in newly reported cases in the last seven days with 2,417,174 infections, followed by Vietnam with 1,776,045.
The 621,328 case tally recorded Thursday is South Korea's highest daily figure since the pandemic began.
But critical cases and deaths remain comparatively low in the country of around 52 million where the majority of adults are fully vaccinated and have received a booster shot, official data shows.
"We have been preparing for an increase in the number of patients since Omicron became dominant," Lee Sang-won, a senior official at the Korea Disease Control and Prevention Agency (KDCA) said Thursday.
But even the government's modelling did not anticipate this many, he said.
"The number is much greater than what was expected," he said.
Health authorities believe South Korea is nearing the peak of an Omicron-driven wave, but Lee said they were recalculating "the scale of the confirmed cases or how long the 'peak period' is going to last".
Once it has passed, officials believe the country will be able to start getting back to normal.
"I think this crisis will be the last major crisis in the overall response to Covid-19," Sohn Young-rae, a senior health ministry official, said Wednesday.
Since the pandemic began in 2020, 11,481 people have died of Covid in South Korea, according to health authorities.
Its total Covid fatality rate stands at 0.14 percent as of Thursday, compared to 0.05 to 0.1 percent for seasonal flu, according to official statistics.
The Omicron surge and its economic implications will pose an immediate challenge to South Korea's new president-elect Yoon Suk-yeol, who narrowly won last week.
Seoul abandoned its "trace, test and treat" approach last month as a dramatic surge in Omicron cases threatened to overwhelm its healthcare system.
Instead of mass testing and aggressive contact tracing, patients with mild or moderate symptoms are now asked to look after themselves at home.
Authorities are also prioritising PCR testing for people aged 60 or older.
The country has continued to relax its social distancing rules, under pressure from small businesses owners who say years-long Covid restrictions had pushed them to the brink.
The government is expected to decide whether to keep current distancing guidelines, such as an 11 pm curfew for businesses, this Friday.
Later this month, Seoul will also begin vaccinating children between the ages of 5 and 11.