It’s relieving that at least other branches of vaccine development are not under the information regime as with COVID.

“However, environmental bacteria complicate the picture. If present before vaccination, memory immune cells primed to destroy the environmental relatives might cross-react with and neutralize the BCG strain before it has a chance to set up an immune response against itself and M. tuberculosis.”

Nobody cared if one already had covid before administering the vaccine and since the vaccine came late many have had a previous infection already. The new mRNA vaccine utilities the body to produce the actual pathogen and with already existing immunity from a previous infection one’s immune system starts to attack the mRNA modified cells and pathogen product.