So far, in South Africa, most people infected are young and their symptoms have been mild.
There is some suggestion that the variant could be causing some slightly different symptoms to Delta – including aches and pains, and no loss of taste or smell – but it’s too early to say for certain.
At the moment, the World Health Organization says there is no evidence that symptoms of Omicron are different to those of other variants.
That means a new cough, a fever and loss of taste or smell are still the main three symptoms to look out for.
Hospitals in South Africa are seeing more young people admitted with more serious symptoms – but many are unvaccinated or have had only one dose.
This suggests that getting two doses and a booster dose is a good way of protecting against disease caused by the new variant, as well as all other variants.
-BBC