(CNN)A mandate to wear face coverings in indoor public places is back for millions of residents -- even those fully vaccinated -- in the San Francisco Bay Area as the highly contagious Delta variant causes a spike in new Covid-19 cases.
Bay Area counties reinstate mask mandate, joining other cities and states as Covid-19 cases surge
Health officers from San Francisco, Santa Clara, Alameda, Contra Costa, Marin, San Mateo and Sonoma counties and the city of Berkeley announced the decision in a joint briefing Monday, joining similar mandates in Los Angeles, Sacramento and Yolo counties that require masks indoors.
The reinstated order affects more than 7 million residents of the Bay Area and will go into effect at 12:01 a.m. Tuesday.
The new order means nearly half of California's population will now be under a mask mandate, regardless of vaccination status.
The Centers for Disease Control and Prevention last week recommended that even fully vaccinated people wear masks indoors in areas with "substantial" and "high" transmission of Covid-19, which includes nearly two-thirds of all US counties as the Delta variant spreads aggressively.
"Indoor masking is a temporary measure that will help us deal with the Delta variant, which is causing a sharp increase in cases, and we know increases in hospitalizations and deaths will follow," said Dr. Naveena Bobba, San Francisco's acting health officer.
Louisiana Gov. John Bel Edwards on Monday temporarily reinstated a statewide mask mandate for everyone 5 years and older when they are indoors and in public. The order goes into effect Wednesday.
"It has become extremely clear that our current recommendations are not strong enough to deal with Louisiana's fourth surge of Covid," Edwards said. "In fact, nobody should be laboring under the misapprehension that this is just another surge. We've already had three of these, this is the worst one we've had thus far."
New York City Mayor Bill de Blasio is strongly encouraging vaccinated people to wear masks indoors, but stopped short of reissuing a mask mandate on Monday in what he said was an attempt to focus primarily on vaccinations.
San Francisco also is seeing its fourth surge of Covid-19 cases, which are increasing at a faster rate than the previous three and infecting even those who have been fully vaccinated against the coronavirus, Health Director Dr. Grant Colfax said Friday.
The group of health officers is urging all residents 12 and over to get vaccinated as soon as possible. About 63% of California's nearly 40 million residents have been fully vaccinated, according to data from the CDC.