As to whether the current batch of mRNA vaccines are "inefficient" against delta, the science is far from settled. There are no changes to the mRNA vaccines co

As to whether the current batch of mRNA vaccines are "inefficient" against delta, the science is far from settled. There are no changes to the mRNA vaccines composition in the booster. Moderna has been testing a lower "dosage" of the booster at 50 mcg vs. 100mcg for the current vaccine, but other than that it's the same stuff it's always been.