South Africa has had a lot of Covid infection, and what they lack for in vaccine induced immunity they perhaps have in infection induced immunity. It's not clear to me which is going to provide better protection from hospitalisation against this new variant; for 2 doses of vaccine at least; the 3rd dose looks transformative against delta.
IndieSAGE:
"Omicron has a growth advantage over Delta in South Africa and has spread rapidly –mostly so far in younger populations. We don’t know if it is more severe once infected.
"The [variant's] advantage seems to be more immune escape than infectiousness –which means we can rely less on population immunity to prevent growth
"It has seeded in many countries worldwide, including the UK. It is likely there are hundreds of Omicron cases here already.
"UK context very different to S Africa:
• Much older population [ETA: South Africa age median = 28]
• Much more vaccinated *and* much more boosted population
• It’s winter here, not summer
• We already have a large Delta wave going on."