From what I have read, it works well against The UK variant and the P1 variant in terms of transmissibility and mild to severe symptoms.
The south African variant is where things get dicey. it has a 10,9 % efficacy in preventing mild to moderate symptoms. The good news is, so far it has a track record of 100% efficacy against SEVERE symptoms.
ANd that is kind of what we want to do... take the shot so we don't die.
Sure there are concerns, but the benefits FAR outweigh the miniscule chance of clots.