Professor Saul Faust, who led the new study, said six different vaccines proved safe and effective as booster shots for people who had received two doses of AstraZeneca or Pfizer/BioNTech.
Public Health Officials in Guateng province estimate that the R value - a key measure used to gauge how fast a wave is growing - could be as high as 3.5. For comparison, the UK s has never been above 1.6.
Official data shows that the proportion of positive Covid tests with a mutation synonymous with the highly-evolved strain is on the rise in England. It suggests Omicron could be behind 0.3% of cases.
The country s National Institute for Communicable Diseases recorded another 16,055 Covid cases in the last 24 hours - with the vast majority in epicentre Gauteng province.