South Korea has encouraged its citizens to take Covid-19 booster shots as more of the elderly fall ill and report vaccine breakthrough infections, driving serious and critical cases to a record.

Severe coronavirus cases jumped from the mid-300s in October to 460 in the last 24 hours, official data showed. Of the severely ill patients, more than 82 per cent were aged 60 and older.

Son Young-rae, a senior health ministry official, told a news conference that the increase is not posing a threat to the country's healthcare system yet, as there are nearly 500 ICU beds available.

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