Bay Briefing: The Bay Area may never reach herd immunity FacebookTwitterEmail Herd immunity may be an unreachable goal in San Francisco and the rest of the Bay Area.Nick Otto/Special to The Chronicle Good morning, Bay Area. It’s Monday, May 10, and high school seniors in San Francisco public schools can return to campus on May 14. Here’s what you need to know to start your day. Finding another way The Bay Area has some of the best COVID-19 vaccination rates in the country, yet the goal of herd immunity is largely off the table now, according to health experts.