Researchers detected this higher load when symptoms were first observed in people infected with the strain, first identified in India.
But it declined over time – to 30 times higher after four days, 10 times after nine days and it fell in line with other Covid variants after ten days.
The higher load means the virus spreads far more easily from person to person, increasing infections and hospitalisations, the Korea Disease Control and Prevention Agency (KDCA) said on Tuesday.
“But it doesn’t mean Delta is 300 times more infectious… we think its transmission rate is 1.6 times the Alpha variant, and about two times the original version of the virus,” Lee Sang-won, from the KDCA, said.
Researchers said it underscored why people needed to get tested quickly and avoid in-person meetings when they develop Covid-19 symptoms.
Meanwhile, deaths in Britain are above average for the sixth week running, with experts warning that a year of disrupted healthcare may be starting to show in the figures.
Elsewhere, the Australian prime ministers has said that continuous lockdowns are “unsustainable”, marking a shift in policy away from the rigid restrictions that have characterised the country’s Covid response.
“That is our goal – to live with this virus, not to live in fear of it,” Scott Morrison told reporters.
His remarks came as Jacinda Ardern, New Zealand’s prime minister, extended her country’s lockdown until the end of the week in response to 107 Covid cases. (Daily Telegraph)