Students on the UC Berkeley campus on March 4, 2020 in Berkeley, California.

Gabrielle Lurie | San Francisco Chronicle | Hearst Newspapers via Getty Images

California State University and the University of California announced Thursday that all students, staff and faculties who want to be on campus must be vaccinated against Covid.

California’s two university systems are the largest of the dozen higher education institutions that require vaccinations for the fall semester. More than 1 million students and employees are affected by the decision. Students and staff can request exemptions for medical or religious reasons, as would be the case with other mandatory vaccines.

“Together, the CSU and UC enroll and employ more than 1 million students and employees on 33 major university campuses. This is the most comprehensive and rigorous university plan for COVID-19 vaccines in the country,” said Cal State Chancellor Joseph I. Castro .

Universities were reluctant to make the decision beforehand due to legal issues surrounding the requirement of vaccines that have not been fully approved by the Food and Drug Administration. Pfizer-BioNTech and Moderna vaccines are sold under emergency clearance, but the companies expect FDA approval by fall.

Both universities plan to work mostly personally for the semester.

Vaccines are “a key step people can take to protect themselves, their friends and family, and our campus communities, while helping end the pandemic,” said UC President Michael V. Drake, a medical doctor.

Some health experts believe that the need for vaccinations for colleges and universities will help stop the spread of Covid among young people who are increasingly at risk for serious illnesses due to variants that mutate and spread rapidly.

California recorded nearly 2,000 new cases of Covid-19 on Wednesday, and a “double mutant” variant of Covid was recently discovered in the state. The state plans to reopen stores by June 15 while maintaining a mask mandate. Almost half of the adults in the state have received at least one dose of a coronavirus vaccine.