I *knew* vaccines were not tested in the trials for transmission, yet I also know they reduced transmission substantially pre-Delta.

How? Because people studied the effect of the vaccines in the real world, and did find they reduced transmission. E.g. https://t.co/Ql29hxqU68 pic.twitter.com/UnJISvT5fB

— Marco Piani 𝕏 (@Marco_Piani) October 12, 2022