South African scientists see no sign that the omicron coronavirus variant is causing more severe illness, they said on Friday, as officials announced plans to roll out vaccine boosters with daily infections approaching an all-time high.

South Africa alerted the world to omicron late last month, prompting alarm that the highly mutated variant could trigger a new surge in global infections.

Hospital data show that COVID-19 admissions are now rising sharply in more than half of the country's nine provinces, but deaths are not rising as dramatically and indicators such as the median length of hospital stay are reassuring.