South Korean health officials on Wednesday approved Pfizer's COVID-19 vaccine for children aged 5 to 11, expanding the country's immunisation programme in the face of a massive omicron outbreak that is driving up hospitalisations and deaths. The Korea Disease Control and Prevention Agency reported a record 171,452 new virus cases on Wednesday, nearly a 40-fold increase from levels in mid-January when omicron first emerged as the country's dominant strain. The 99 new deaths were the highest daily tally since Dec. 31, when the country was grappling with a delta-driven surge that buckled hospital systems.