The University of California system will now require all of its students and staff who want to return to campus this fall to be vaccinated against COVID-19.

Regent Eloy Oritz Oakley told the San Francisco Chronicle on Tuesday that UC President Michael Drake "does plan to move forward with the vaccine mandate."

It's an about-face for the school system, which has 280,000 students and 227,000 faculty and staff across 10 campuses. 

Drake, who is also a medical doctor, said in an April proposal that while all students and staff are strongly encouraged to get vaccinated, it would only be mandated "once a vaccine has full approval from the U.S. Food and Drug Administration."

A spokesman for the University of California said that after hearing input on that April proposal, the school system has decided to implement the mandate. 

"This policy has evolved since the original April proposal designed to encourage and subsequently incorporate community input," the spokesman told Fox News Tuesday. 

"Based on that feedback and additional medical studies on the efficacy of the Pfizer, Moderna, and Johnson & Johnson vaccines, the policy being finalized in July would be implemented immediately and allow for the use of vaccines currently approved by the [FDA] under emergency use authorization."

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The FDA has so far issued an emergency use authorization for three vaccines made by Moderna, Pfizer-BioNTech, and Johnson & Johnson. 

It's currently unclear when the vaccines will get full approval. Pfizer applied for full authorization of their vaccine on May 7, while Moderna applied for full authorization on June 1. 

In this April 8, 2021, file photo, Kent State University student Jarrett Woo gets his Johnson & Johnson COVID-19 vaccination from Kent State nursing student Allie Rodriguez in Kent, Ohio. (AP Photo/Phil Long, File)

In this April 8, 2021, file photo, Kent State University student Jarrett Woo gets his Johnson & Johnson COVID-19 vaccination from Kent State nursing student Allie Rodriguez in Kent, Ohio. (AP Photo/Phil Long, File)

Drake sent a letter to chancellors throughout the system on Friday notifying them of the new policy. He said the final policy and implementation guidelines should be ready by mid-July. 

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State officials said 66.4% of Californians have received at least one dose of a vaccine and 55.6% are fully vaccinated. 

Several private schools in California – including Stanford University and the University of Southern California – have already said they will require students and staff to be vaccinated this fall.