Haunted by Past Virus Surges, California Leans on Masks and Vaccines

SACRAMENTO — Exactly one month after Gov. Gavin Newsom triumphantly announced California’s “grand reopening” from more than a year of health restrictions, Los Angeles County said on Thursday that face masks would again be required indoors starting this weekend.

The proclamation — along with a warning from the University of California that most unvaccinated faculty, staff and students would be barred from its campuses this fall — underscored the gathering concern that the coronavirus may be poised for a resurgence, although not one nearly as bad as past spikes.

Every state has reported an increase in the number of new virus cases in recent days. California’s figures have nearly tripled over the past month, largely because of San Bernardino and Los Angeles, but the current rate of 3,000 new cases a day is a blip compared to the winter peak, when there were more than 44,000.

California is doing slightly better than the national per capita average and far better than hot spots in Arkansas and Louisiana. In parts of Missouri, hospitals have been stretched thin by an influx of coronavirus patients.

Scientists say that the some 160 million people across the country who are fully vaccinated are largely protected from the virus, including the highly contagious Delta variant. But particularly in places like the South, where vaccination rates are among the lowest in the country, the risk of a fresh spike is serious, said Dr. Peter Hotez, a vaccine expert at Baylor College of Medicine.

“If you have been lucky enough to escape infection previously and you’re not vaccinated, your luck is about to run out,” Dr. Hotez said.

Mr. Newsom echoed that concern this week at a public appearance in the working-class Southern California community of Bell Gardens.

“I cannot impress upon you more the power of getting vaccinated,” the governor said. “If we want to extinguish this pandemic, this disease, we’ve got to get vaccinated. Period. Full stop.”

Fifty-one percent of Californians are fully vaccinated, well below the levels in some Northeastern states but above the national rate. Vaccines are free and currently available to anyone 12 or older.

In Los Angeles County, where public health officials had already been recommending — but not requiring — masks indoors, new cases have spiked more than 200 percent in the past two weeks, to more than 1,000 daily. The reinstated masking requirement will take effect just before midnight on Saturday.

Elsewhere in the state, Sacramento and Yolo Counties also began recommending masks indoors this week. San Francisco officials on Thursday targeted a plea to Black and Latino residents to get vaccinated, noting that those groups were more than twice as likely to contract Covid-19 than the citywide population.

Dr. Anthony S. Fauci, the nation’s top infectious-disease expert, has described the Delta variant as “the greatest threat in the U.S. to our attempt to eliminate Covid-19.” More than 63,000 Californians have died of the coronavirus. Fewer than 40 deaths statewide are being announced on most recent days, down from more than 500 a day during much of January.

At the 10-campus University of California system, President Michael V. Drake said in a letter to chancellors that the current research, both from medical studies and the university’s own infectious-disease experts, clearly pointed to the need for a vaccine mandate for anyone who was going to be on campus.

“Vaccination is by far the most effective way to prevent severe disease and death after exposure to the virus and to reduce spread of the disease to those who are not able, or not yet eligible, to receive the vaccine,” wrote Dr. Drake, who is also a physician.

The vaccine requirement will apply to students and employees alike, as well as participants in athletic and study-abroad programs, he said, and will be enforced even if the vaccines remain under emergency use authorization.

Students without approved vaccine exemptions will be barred from campus housing, events, facilities and classrooms, the policy noted. While there would be “limited exceptions, accommodations and deferrals,” not all classes will be offered remotely.

The university, which serves more than 285,000 students at campuses from San Diego to Berkeley, had indicated earlier that inoculation would be required only after the Food and Drug Administration gives at least one of the three vaccines — Pfizer-BioNTech, Moderna and Johnson & Johnson — full approval. As medical studies demonstrated their efficacy, university officials decided to go forward.

Hundreds of colleges and universities, including Stanford, the Claremont Colleges and the University of Southern California, have mandated vaccines for the fall, according to The Chronicle of Higher Education. But the University of California mandate is the most sweeping so far by a public university.