SAN FRANCISCO >> Two of the nation’s largest university systems say they intend to require COVID-19 vaccinations for all students, faculty and staff on University of California and California State University campuses this fall.

Several U.S. colleges and universities also have said they plan to require the vaccination. But today’s joint announcement from the 10-campus University of California and the 23-campus California State University is the largest of its kind in American higher education.

The CSU system in the nation’s biggest four-year college system, with about 485,000 students and tens of thousands of staff, while the UC system has more than 280,000 students.

“Together, the CSU and UC enroll and employ more than one million students and employees across 33 major university campuses, so this is the most comprehensive and consequential university plan for COVID-19 vaccines in the country,” CSU Chancellor Joseph I. Castro said in the statement.

Stanford University also announced a mandate today requiring all of its 19,000 students to be vaccinated when classes start in the fall.

The Pfizer and Moderna vaccines are being distributed under the Food and Drug Administration’s emergency authorization. Health experts expect formal approval of at least one by the fall. The Johnson & Johnson vaccine is on pause due to concerns about blood clots.

CSU spokeswoman Toni Molle said the timing of a formal mandate will depend on when the FDA gives full authorization to one or more of the vaccines and also on discussions with labor unions. It could come before classes start or after.

“We are announcing now so that students and employees have time to receive a vaccination in the event that we have implemented a requirement,” she said.

Students who have an approved exemption for medical or religious reasons will be required to undergo regular COVID-19 testing.