Following federal guidance, county officials are also urging local residents to wear face masks indoors to reduce the spread of the delta variant.
"The rate of COVID-19 cases in San Diego County is rated 'high' by the Centers for Disease Control and Prevention," county officials said in a statement released shortly after 5:30 p.m. on Tuesday. "New research reveals the delta variant is much more transmissible and expected to lead to a growing number of cases in vaccinated individuals while primarily striking the unvaccinated. The county of San Diego will follow the latest CDC guidance in recommending the universal wearing of masks by both vaccinated and unvaccinated individuals in indoor public settings."
Mask-wearing has remained a requirement indoors across California for unvaccinated people. However, enforcement of the requirement was based largely on a kind of honor system, making it uncertain if unvaccinated residents were abiding by the rule.
Full coverage of the COVID-19 outbreak and how it impacts you
The Centers for Disease Control and Prevention changed course Tuesday on some masking guidelines, recommending that even vaccinated people return to wearing masks indoors in parts of the U.S. where the delta variant of the coronavirus is fueling infection surges.
Citing new information about the variant's ability to spread among vaccinated people, the CDC also recommended indoor masks for all teachers, staff, students and visitors at schools nationwide, regardless of vaccination status.
In other developments, President Joe Biden said his administration was considering requiring all federal workers to get vaccinated. His comments came a day after the Department of Veterans Affairs became the first federal agency to require its health care workers receive the vaccine.
Biden dismissed concerns that the new masking guidance could invite confusion, saying Americans who remain unvaccinated are the ones who are “sowing enormous confusion.”
“The more we learn about this virus and the delta variation, the more we have to be worried and concerned. And there’s only one thing we know for sure — if those other 100 million people got vaccinated, we’d be in a very different world,” he said.
The White House quickly pivoted on its own masking guidance, asking all staff and reporters to wear masks indoors because the latest CDC data shows that Washington faces a substantial level of coronavirus transmission.
The CDC's new mask policy follows recent decisions in Los Angeles and St. Louis to revert to indoor mask mandates amid the spike in COVID-19 infections. The nation is averaging more than 57,000 cases a day and 24,000 COVID-19 hospitalizations.
The guidance on masks in indoor public places applies in parts of the U.S. with at least 50 new cases per 100,000 people in the last week. That includes 60 percent of U.S. counties, officials said. New case rates are particularly high in the South and Southwest, according to a CDC tracker. In Arkansas, Louisiana and Florida, every county has a high transmission rate.
Case rates in San Diego seem to far exceed the federal guideline -- according to the latest figures, from July 11-24, the countywide rate is 225 per 100,000 residents. It should be noted that, however, that the CDC is using a seven-day average.
In concluding their statement, San Diego County officials pointed back to the critical element in vanquishing the pandemic: Vaccinations.
"Masks are an added measure; vaccinations are critical for getting back to the things we love."
The Associated Press and City News Service contributed to this story -- Ed.