Delta has improved in cell machinery and better cleavage site (point where its spike protein splits in half when entering the cell) but outside of it is well re

Delta has improved in cell machinery and better cleavage site (point where its spike protein splits in half when entering the cell) but outside of it is well recognizable for current vaccine induced antibodies. There is no need for a new vaccine against it, just more antibodies to clear normally higher viral load that comes with it, so more of the same vaccine is better than something completely new. For data points, data from Israel states that third shot has been more tolerable than the second one in general with less frequent and less serious side effects. I will get mine in coming week and I can tell you about my personal experience - two previous shots gave me just pain in the injection site. Pfizer and Moderna chose a little different optimization strategy - Moderna went with higher mRNA dose (3x higher than Pfizer), Pfizer tested also smaller dose, saw that it produces about the same result but with less side effects and went with lower concentration. Now it appears that immunity from Moderna shot is longer lasting but it really does have more side effects than Pfizer. I think it is also the reason why the booster dosage of Moderna vaccine is half of its initial dosage. So perhaps it still will provide a little better immunity having about 1.5 mRNA concentration of Pfizer and has now about the same level of side effects. Hard to say at the moment.