The University of California's Berkeley campus is under strict lockdown following a surge of COVID-19 cases among the school's 2,000 on-campus students.
According to the university's website, the campus outbreak began in mid-January. 400 people have tested positive since then. According to NBC News affiliate KCRA3, a week-by-week breakdown of publicly available data shows that 200 of those cases were diagnosed in February.
Most of the positive cases are among students at the school, according to KCRA3.
The initial lockdown measures were put into place on Feb. 1, when all students living in "dorm-style residence halls" were ordered to "self-sequester" until at least Feb. 8, according to KCRA3. Under the lockdown, students are required to stay in their rooms at all times unless they are seeking medical care, using the residence hall's assigned communal bathrooms, or picking up food from dining kiosks located outside their residential buildings. Students are tested for COVID-19 twice a week, and the school "strongly" advised students against leaving campus to stay with family or friends due to the risk of spreading the virus.
The lockdown was recently extended until at least Feb. 15. The school's website noted on Tuesday that "new cases are slowing down," but since the virus has a 14-day incubation period, "it is too early to be sure this current surge is contained."
An email sent from the school, which is available online, listed further restrictions on students.
"You may NOT leave your room for solo outdoor exercise," read the email, adding that this was a change from earlier restrictions. "We are working with the City of Berkeley to determine whether outdoor exercise may be permitted, and we will provide more information on this in the near future."
The outdoor activities ban is new: The Centers for Disease Control and Prevention (CDC) have referred to outdoor activities as a "safer choice," so long as people stay at least six feet away from people who are not in their household and wear appropriate facial coverings. Over the summer, experts told TODAY that outdoor exercise would be a relatively safe activity.
"If you're outside, if you're spread out pretty far, if you're not breathing hard, the risk should be extremely low," said Dr. Lawrence Stanberry, director of the programs in global health at Columbia University Vagelos College of Physicians and Surgeons in New York, in July.
California governor Gavin Newsom has also encouraged outdoor exercise, even when the state was under strict lockdown periods.
University spokesperson Janet Gilmore told KCRA3 that the school hopes the strict rules, which are being enforced by an increased number of residential hall staff and security guards, will limit further cases of the virus.
"We believe that small, off-campus gatherings are linked to the outbreak," said Gilmore. "The various terms of the self-sequester period are part of the effort to prevent further spread."