It’s basically identical to other real world studies which have shown 89-91% effectiveness in the general population against the prevailing mixture of variants this winter and spring in the US and the UK. Which is in turn only slightly lower than the reported 94-95% effectiveness in the clinical trial environment last summer. Long story short it’ll be a long time before the mRNA vaccines aren’t effective.

efficacy is similar due to conservation of the receptor binding domain[RBD] of spike protien[S] the RBDab is billed as the gold standard neutralizing antibody as when it binds to RBD of the S protien, that particular S protien is no longer able to bind to its ligand [ACE2]

should we see a variant that escapes this RBD Antibody mechanism then there will be a possibility of escape, and concommitant requirement to tweak the vaccine antigen.

So you don’t get it and pass it on to the unvaccinated in the window that you are infected and your body is fighting it off.

Depends on what you mean by "effective" (i.e. are you talking about infection, hospitalisation or death?), and relative to what (i.e. ancestral wild type vs Alpha vs Delta).

If you're talking Alpha vs Delta and about hospitalisation/death, then the vaccines are actually marginally more effective against Delta than Alpha according to data from Public Health England (although there's significant overlap in the confidence intervals).