Christy Yu / Daily Nexus

UC Santa Barbara’s decision to return to in-person instruction — announced by Chancellor Henry T. Yang on Jan. 21 — resembled the actions of nearly every UC campus, with all universities, except UC Merced, opting to hold in-person classes beginning Jan. 31.

The UCs have since affirmed their decision to return to in-person instruction through messages to their individual campus communities, providing updates on their continuing COVID-19 mitigation efforts and analysis of campus positivity rates and cases.

Despite the UC’s confidence in their respective mitigation efforts, the LA Times reported that on Jan. 31, students at UCLA participated in a sit-in, and students at UC Davis and UC Irvine are also organizing walkouts, in advocacy for continued access to online learning options.

Testing, Vaccination & COVID-19 Infection Models

As of Feb. 1, 3,011 UCSB students and employees tested positive since Sept. 19, 2021 through both on-campus testing or off-campus tests, and the university reported 328 active cases, according to the UCSB COVID-19 dashboard

“The Omicron surge now appears to be waning. Our campus testing and surveillance program already has seen the case positivity rate in our UCSB community drop precipitously (more than 40% from week one through week three),” the COVID-19 Response Team said in a Jan. 26 email to the student body.

UCSB COVID-19 coordinator Dr. Scott Grafton, professor of psychological and brain sciences, said in a UCSB Current article that UCSB should expect high levels of immunity from the virus due to high vaccination rates coupled with students gaining immunity to omicron via infection. 

“Up to 90% of the campus will be immune to omicron because they have either had it or are protected by vaccines,” Grafton said in the Current.

Up to 40% of the campus community will gain that immunity via infection, Grafton said, according to university models based on Santa Barbara County case rates amongst vaccinated individuals.

He explained how UCSB used a standard SIR model for disease spread to arrive at this statistic.

“It assumes that 50% of cases are unreported, similar to what has been shown with Alpha and Delta variant surges,” Grafton said in a statement to the Nexus. “In addition, it incorporates evidence from multiple publications showing that vaccine efficacy for Omicron is approximately 50% compared to Delta, where efficacy was above 95%. That is, about half the vaccinated population are able to mount an adequate immune response to keep from getting Omicron.”

These models reflect much higher rates of infection than the UCSB COVID-19 dashboard, which reports a 4.31% positivity rate through on-campus testing for the fourth week of instruction. Grafton elaborated on this discrepancy, attributing it to underreporting of those who tested positive off-campus or who had COVID-19 over winter break.

“The dashboard mostly reflects PCR tests of students who are on campus.

Omicron surge began around December 10, when almost no one was on campus,” Grafton said in the statement. 

“It peaked around Jan. 7, when only a fraction of the campus had returned. The vast majority of faculty, staff and students who got Omicron (whether symptomatically or asymptomatically) did so in other places besides campus. We don’t have a count of those infections,” Grafton continued. 

Grafton said that high quality and high quantity of testing are integral for an accurate count of case numbers. 

“We know from prior surges (also true for Omicron) that only about half of people who get COVID get themselves tested (anywhere),” he continued. “Furthermore, the home tests people began using in December miss about 1/3 of the infections in persons who don’t have symptoms. Thus, the dashboard can’t be used to get a good estimation of the total number of Omicron cases.”

In a newsletter sent on Jan. 28, UC Berkeley described its actions as “in line with other UC and west coast universities” and emphasized that no state or federal guidance currently suggests that they pivot to remote instruction.

Cases Decline Throughout UCs

Projections of declining COVID-19 cases and positivity rates played a large role in UC campuses’ decision-making process.

UC Irvine reported a decline in cases from a 17% positivity testing rate from the beginning of winter quarter to 3% by their fourth week of instruction. Similarly, UC Berkeley reported a 4% positivity rate, and UC Davis reported a 1.07% positivity rate for campus tests collected between Jan. 22 and Jan. 30.

“All our models indicate that these numbers will continue to decline (with some fluctuations as some additional students return to their dorms), but we know that we can identify and contain new cases at these numbers,” the UCI COVID-19 Response Center said in a Jan. 27 campuswide email.

COVID-19 Infection Models Predict Low Classroom Transmission 

Multiple UC campuses said that the low risk of transmission within the classroom was a factor in their decision, claiming that there were low or no instances of transmission in conventional classroom settings during Fall Quarter 2021.

According to the UCSB COVID-19 Response Team, no in-class transmission of COVID-19 occurred throughout the fall quarter, except for one known instance — a theater arts rehearsal, during which students remained unmasked and in close proximity for a prolonged period of time.

“There were 89 cases where an individual had COVID and attended class, which worked out to nearly 25,000 exposure events,” Todd Squires, professor of chemical engineering, said in the UCSB Current. “Of all of those, there was not one conventional in-person classroom transmission.”

UCSB modeled the risk of classroom-based transmission specific to the omicron variant in preparation for Winter Quarter 2022. The model factored in the size of the room, number of students, length of exposure and the room’s ventilation, and determined risk to be low — one transmission per 850 typical classroom lectures, according to Grafton.

Squires, who helped to conduct the classroom-level transmission modeling, described how transmission occurs differently between the omicron and delta variants.

“Omicron is different than delta for a number of reasons,” Squires said in the UCSB Current. “It appears to be more transmissible, and it seems to be avoiding the immunity that many of us have.”

UC Berkeley’s administration echoed UCSB’s COVID-19 Response Team’s sentiment. 

“Classrooms have not proven to be vectors of transmission,” UC Berkeley’s Jan. 28 newsletter read. “In particular, the guidance we have been given is that instructors and students wearing appropriate face coverings and fully vaccinated do not face a contagion risk higher than in everyday life.”

“We know that most COVID-19 contagion occurs in social settings, especially those where individuals have removed face coverings to eat or drink,” the newsletter continued.

UC Irvine said that similarly low rates of transmission can be expected with the omicron variant in a message to its campus community.

“We have been consulting with other (non-UC) campuses that have begun in-person instruction. These campuses report that, as with the delta variant, there has been no evidence of classroom transmission within a highly vaccinated and masked campus community,” the statement read. 

UC Schools Use Different Mitigation Efforts

During their return to in-person instruction, UCLA and UC Davis are continuing their policy of requiring weekly testing for vaccinated students living in university housing. UC Berkeley requires monthly testing for vaccinated individuals living on campus, while UC Irvine tests one quarter of its students every week. All other UCs, including UCSB, lack periodic testing requirements for fully vaccinated students.

The difference in requirements partly reflects the varying testing capacities of each university. The Daily Bruin detailed the disparities of COVID-19 testing accessibility across UC campuses. In particular, universities with established medical centers and university-affiliated hospitals have greater resources to expend, according to the Bruin.

UC Merced, UC Riverside and UCSB are among campuses with only one available testing site. In contrast, UCLA and UC San Diego have launched the distribution of free COVID-19 testing kits through vending machines located around campus. 

UCLA processes an average of 30,000 tests per week, according to UCLA spokesperson Bill Kisliuk, and Davis’ weekly average hovers around 25,000, according to their COVID-19 dashboard.

UCSB can test about 9.5% of its students weekly through its Loma Pelona facility and drop-off testing kits system — a fraction of its sister campuses’ capacities.

“As of mid-January, the university is capable of processing 2,500 COVID-19 PCR tests per day. Many of these tests are performed in our clinically certified UCSB COVID-19 laboratory and some are sent out to nearby laboratories,” the Current said in a Jan. 26 release.

Certain UCs felt the operational strain of increased testing in January, as students were required to obtain mandatory campus testing upon their return despite staffing shortages amongst health and medical personnel and limited supplies. 

At UC Berkeley, more than 60 individuals volunteered extra shifts or were temporarily reassigned to support housing and health services, according to their Jan. 28 newsletter.

Dr. Stu Feinstein, coordinator of UCSB’s COVID-19 Response Team and professor in the department of molecular, cellular and developmental biology, explained how the university originally intended to test only a few hundred unvaccinated students before Fall Quarter 2021 and had to ramp up its capacity substantially in light of the emergence of the delta variant, and now again with omicron.

“In the fall we went from thinking about 500 tests over a week to 10,000 for move-in week,” Feinstein said in the Current. “In the lab we had to have enough supplies and people to perform 10,000 tests — that’s a 20X increase. We had to hustle. Now this winter quarter of 2022, the same thing has happened because of the omicron variant.”

A version of this article appeared on p. 1 of the Feb. 3, 2022, print edition of the Daily Nexus.


Nisha Malley
Nisha Malley (she/her/hers) is the County News Editor for the 2022-23 school year. Previously, Malley was an Assistant News Editor for the 2021-22 school year. She can be reached at