Students at more than 30 colleges won't be allowed back unless they're vaccinated against COVID-19

• California State University and the University of California are the latest schools to announce COVID-19 requirements before returning to campus.
• The California schools have said their mandate was dependent on the FDA approving the vaccines.
• Many colleges remain divided about whether to implement a vaccine mandate for students and staff.

More than 30 colleges won't let students return to classes if they aren't vaccinated against COVID-19.

California State University and the University of California are among the latest schools to announce they will require the vaccine for staff and students, the universities announced in a statement.

Together, more than 1 million staff and students attend the two universities, which have a total of 33 campuses.

"The state of California has been a leader in the administration of COVID-19 vaccines, and Californians receiving a vaccine has led to significantly reducing the transmission of COVID-19 in our state," CSU Chancellor Joseph I. Castro said in the written statement. "We will continue to strongly encourage all members of our respective university communities to receive a COVID-19 vaccination as soon as it is available to them."

The requirement went into effect upon the FDA's approval of one or more of the vaccines.

The California universities join a growing list of other institutions that will make the vaccine mandatory in 2021.

The list includes Yale University, American University, Georgetown University, Stanford University, Manhattanville College, Vassar College, Grinnell College, Bowdoin College, George Washington University, Emory University, Clark Atlanta University, Morehouse College, Spelman College, College of the Atlantic, Seattle University, Fairleigh Dickson University, and Assumption University, CNBC reported.

Duke University, Brown University, Northeastern University, the University of Notre Dame, Syracuse University, Ithaca College, Cornell University, Rutgers University, DePaul University and Columbia College, Nova Southeastern University, Roger Williams University, Fort Lewis College, and St. Edwards University have made similar announcements, according to CNBC.

Many colleges remain divided about whether to implement a vaccine mandate for students and staff. Opponents say vaccine mandates trample on personal liberties, freedom or religion and medical choice. A recent poll from Monmouth University found that about one-in-five American adults are unwilling to get the COVID-19 vaccine.

Proponents say herd immunity through mass vaccinations is the only way to end the pandemic and resume normal life.

"Receiving a vaccine for the virus that causes COVID-19 is a key step people can take to protect themselves, their friends and family, and our campus communities while helping bring the pandemic to an end," UC President Michael V. Drake said in a statement.