It may have enough spike changes to evade the antibodies originally made by the vaccines. That would mean more vaccinated people could get infections. But the vaccines did two things that are going to fight any variant:

1. They made activated T and B-cells that respond to much wider viral epitopes than antibodies. When those T-cells encounter any corona virus (including SARS1 or MERS) they quickly get B-cells cranking out antibodies specific to that new variant. So the race between the virus and the immune system is fixed way in favor of the immune system.

2. If your immune system has a couple of months following vaccination, some "antibody evolution" takes place in the lymph nodes and other germinal centers. You start making all sorts of related, but different, antibodies. Pretty much antibodies against every variant possible. Evolution has selected for us making those related antibodies, just to keep up with virus mutation. That's called "co-evolution" and it's a very real thing.

What we should be looking for is how many vaccinated South Africans are ending up seriously ill or dead. The hospitalized number is not very useful in a country with so many poor people and lots of AIDS patients. Too many rich people get hospitalized when they don't need it, and way too many poor people have to just die at home. But eventually, a more deadly variant may emerge. The vaccinated or previously infected will do well. Non-immune people will die at a much higher rate.

Educating anyone benefits everyone.