If you were paying attention, note the difference between saying it will prevent all retransmission versus reducing it, which is what happened. Also, try to compare what actual medical experts said as opposed to the political entertainers whose talking points you're repeating. The actual medical experts were quite clear on this, and Biden has been pretty clear that breakthrough infections are possible — hence the interest in masks to prevent spread and vaccination to mitigate the damage for the people who we know statistically will catch it.