A day after Los Angeles reinstituted its mask mandate, a coalition of Bay Area health officers including those representing San Francisco and Alameda counties issued a joint statement urging residents to wear their masks again voluntarily.

We're boomeranging yet again, with increasing reports of breakthrough cases of COVID among the vaccinated and a rapid rise in new cases among the unvaccinated, likely driven by the Delta variant. And local health officers are telling people that masks should be going back on in public spaces.

"Out of an abundance of caution, people are recommended to wear masks indoors in settings like grocery or retail stores, theaters, and family entertainment centers, even if they are fully vaccinated as an added layer of protection for unvaccinated residents," the joint statement reads. Notably, it did not mention bars, nightclubs, and restaurants, which have now been open mask-free for just four weeks.

The statement was signed by the health officers of Alameda, Contra Costa, Marin, San Francisco, San Mateo, Santa Clara, and Sonoma counties — with Solano County ever wanting to be the odd one out.

On Thursday, SF Mayor London Breed went to the Bayview to plead with residents there to go get vaccinated, and the city's Director of Public Health Dr. Grant Colfax compared getting COVID post- and pre-vaccination as "sniffles versus suffocation."

As reported yesterday, average daily new cases in SF have jumped from 10 a month ago, on June 15, to 42. Experts anticipated that a jump in cases would likely occur following reopening of businesses around the country, and that has proven to be the case in nearly every state — with the highly contagious Delta variant now the dominant strain across the country.

As Dr. Bob Wachter, chair of UCSF's Department of Medicine, said in a tweet, "If you're wondering how bad Delta really is, even in highly vaccinated SF (76% of >age 12 fully vaxxed) & still w/ a lot of masking (most folks in stores), we're seeing a pretty steep Covid uptick."

Wachter added a personal note saying, "I'm back to double-mask in stores. Still indoor dining but might abort if trends continue."

San Francisco's Health Officer Dr. Susan Philip said in a statement Friday, "We are asking our residents to collectively come together again in this effort to stem the rising cases until we can assess how our hospital capacity will be impacted."

The majority of breakthrough cases among vaccinated people appear to be fairly mild, and the majority of hospitalizations appear to be among the unvaccinated, but what's clear is that the dream of "herd immunity" is still just a dream in San Francisco and elsewhere in the Bay Area. One expert retweeted by Wachter, Dr. Eric Feigl-Ding, an epidemiologist and senior fellow at the American Federation of Scientists, says, "Vaccines definitely work, but we have to dispel the notion that 1 shot for 70% is enough. We likely need 85%+ double vaccinated coverage with 2x more contagious Delta."

CDC Director Dr. Rochelle Walensky said in a statement Friday that the nation is facing a "pandemic of the unvaccinated," but she added that "communities that are fully vaccinated are generally faring well."

The Bay Area health officers urged all businesses to "adopt universal masking requirements for customers entering indoor areas of their businesses to provide better protection to their employees and customers." And they said they would revisit this recommendation in the coming weeks based on transmission rates, hospitalizations, and other data.

So, mask up again this weekend, everybody. Sorry that this is fucking with the whole "yay it's over" vibe, but you should know the drill by now.