Public health officials from seven counties in the San Francisco Bay Area, including in the namesake city itself, issued recommendations to wear face coverings indoors to slow the spread of COVID-19 on Friday. Officials from the Southern Nevada Health District said the same, which includes Las Vegas. The recommendations apply to those who have received coronavirus vaccines and those who have not. The recommendation comes the day after Los Angeles County reinstated its indoor mask mandate, a more stringent requirement than the guidance in Northern California and Nevada. The change comes as the more contagious and deadly Delta variant surges among the unvaccinated, especially in Los Angeles, which has once again become a hotspot of new infections and hospitalizations in recent weeks.