Vaccine mandates were always about preventing transmission. There isn't great data yet, but Omicron seems pretty good at infecting vaccinated people, so I suspect people with breakthrough cases still transmit it somewhat well. Santa Clara county is heavily vaccinated, but Omicron was still its biggest wave by far.
Pre-Delta, mandates made sense (though the vaccines came too late for this to ever be practical). With Delta, the case was shakier. With Omicron, they're really only effective at preventing severe disease. That's huge for saving lives, not so much for preventing transmission.
Pre-Delta, mandates made sense (though the vaccines came too late for this to ever be practical). With Delta, the case was shakier. With Omicron, they're really only effective at preventing severe disease. That's huge for saving lives, not so much for preventing transmission.