On Tuesday, the President of the UC system said chancellors might include the return of remote instruction when students come back from the holiday break.
Universities are being told they will need to come up with a plan for this January that "mitigates public health impacts."
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The UC system states that students, faculty, and staff must keep their vaccination status up to date under existing policy.
That policy mandates booster doses for those who are eligible.
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Several UC campuses in Southern California, including San Diego, Irvine, Riverside and Los Angeles, announced they would return to remote learning following the break.
UC Merced resumes on January 18. Administrators say it's currently assessing the situation and urges those eligible to get their booster now.