Working in serum different than real world. Nvax showed 50 or 60% effective against S African variant, and I think J&J the same in trials reported last week or so. Astrazeneca 0% effective against the variant. Pfizer and MRNA vaccines not tested in trial vs that variant and no real world reports yet .. except Israel shows it works 95% as in trial .. on 4M of their 9M citizens vaccinated, but that does not include S African variant since not prevalent there yet.
Most vaccines seem to provide some effectiveness to prevent symptoms from S African variant, just not as good. Still need to see real world results from the mRNA vaccines.