According to the announcement, a "rapid rise in COVID-19 cases locally and across the country" forced university administrators to make the decision.
"We write to inform you that for the first three weeks of January we will take steps to reduce density on campus by moving much of our learning and work remotely. Please know that we do not take this step lightly. It is prompted by the rapid rise in COVID-19 cases locally and across the country, as well as the growing presence of the highly transmissible Omicron variant," the announcement reads.
The Harvard University administrators wrote that the decision to shift classes online was made with "the health and safety of our community as our top priority."
Faculty, staff, and researchers are encouraged to work remotely for the first three weeks of January.
Harvard University's winter session begins on Jan. 14, and the Spring semester begins on Jan. 24.
Most students will be studying remotely unless they have an "authorization" from their school to return to campus, according to the announcement, and states that some programs with essential in-person requirements will continue on-campus.
"Some programs will continue in person, for example those with essential in-person laboratory or patient-centered clinical requirements," the announcement states.
The administrators wrote that later in January, the university could return to "more robust on-campus activities," but noted that is dependent on public health conditions.
Yale University emailed the campus community on Saturday night and announced that all in-person exams will shift to a remote format, and encouraged students to head home.
"While Yale has not experienced the same increase in COVID rates as some other universities, we know that many of you are concerned about remaining on campus during the finals period. Although the risk of transmission during in-person examinations is small, we want you to be able to go home now," the email from Yale University administration read.
The email also said that while classes for the spring 2022 semester are still planned to begin on Jan. 18, students should "plan for the possibility that some or all activities will take place remotely at the outset of the semester."
Harvard isn't the first university to announce a shift to virtual learning for most of January.
Stanford University also announced a shift to online learning for most students during the first two weeks of the winter quarter in January.
A Harvard University spokesperson declined to comment further and referred Fox News to the announcement.