First, vaccinated folks clear the virus faster, so the overall time of infectiousness is lower. https://globalbiodefense.com/2021/12/04/vaccinated-people-clear-

First, vaccinated folks clear the virus faster, so the overall time of infectiousness is lower. https://globalbiodefense.com/2021/12/04/vaccinated-people-clear-covid-faster-less-time-with-high-virus-levels/ https://globalbiodefense.com/2021/12/04/vaccinated-people-cl... Second, fewer vaccinated people have breakthrough infections in the first place, so overall spread is lowered because of vaccinations.