The vaccines did inhibit infection and transmission of the earlier strains, which replicated lower in the lungs. They don’t for Omicron, which preferentially re

The vaccines did inhibit infection and transmission of the earlier strains, which replicated lower in the lungs. They don’t for Omicron, which preferentially replicates in the upper airways, which have less of an immune response. This is why omicron is more transmissible but less deadly. Note that there are nasal spray vaccines in development which stimulate a stronger immune response in that area and potentially restore the transmission-inhibiting ability.