LOS ANGELES (AP) — Los Angeles County will again require masks indoors even when people are vaccinated. Meanwhile, the University of California system announced Thursday it will require coronavirus vaccinations for students, faculty and staff to return to campuses this fall.

The moves are prompted by a sharp increase in virus cases, many of them the highly transmissible delta variant that has proliferated since California fully reopened its economy on June 15.

LA County has been recording more than 1,000 new cases each day for a week and the health officer says there is now “substantial community transmission.”

On Thursday, there were 1,537 new cases, and hospitalizations have now topped 400.