
In the last year, vaccinated people in California were seven times less likely to get COVID-19 than unvaccinated people.
The same trend is playing out in Berkeley schools, where vaccinated Berkeley Unified students over 12 years old were nearly six times less likely to get COVID-19 than unvaccinated students, according to data shared Monday by the district.
Of the 4,915 secondary students in the district, 44 have contracted COVID-19 from the start of the school year until Nov. 15. And of these cases, 18 (40%) were breakthrough infections in fully vaccinated students. (A case hits the dashboard only if a student was on campus during their infectious period.)
That’s 26.42 cases per 1,000 unvaccinated students, compared with only 4.57 cases per 1,000 vaccinated students. (Berkeley students between 5 and 11 years old, who were just approved to get the vaccine in November, were not included in the data provided by the district.)
There’s one caveat that comes with school data: We don’t know exactly how often students are tested for the virus. At the secondary level, only student-athletes on a handful of sports teams participate in surveillance testing, and unvaccinated students have to get tested after an exposure while vaccinated students don’t, per California’s “modified quarantine” policy.
Still, the data mirror statewide trends showing lower rates of infection in vaccinated people. And in Berkeley, where vaccination rates are high, there have been only two small-scale outbreaks at Berkeley schools since the start of the pandemic.
Vaccines have proven even more effective against severe illness. In California, unvaccinated people were 12.5 times more likely to be hospitalized with COVID-19 than fully vaccinated people, though the vaccine’s effectiveness may be waning, according to state data from Nov. 7, 2020, through November 2021. The virus has proved to be far less deadly for children under 18 years old, who account for just .1% of deaths in California caused by COVID-19.
Dr. Kim Rhoads, an associate professor of epidemiology at the University of California San Francisco, said there’s much that individual district data do not show, including the severity of cases, the mask-wearing habits of those infected, and the kind of vaccine infected individuals received. (The one-shot Johnson & Johnson vaccine has proven to be less effective in preventing hospitalization, and may be less effective in preventing infection, than the Pfizer or Moderna vaccines.)
“The vaccine was never promised to prevent the transmission of COVID,” Rhoads said, only to reduce transmission and risk of serious illness, adding that vaccines would effectively stop the virus if everyone were vaccinated.
About 80% of Berkeley students 12 and up are vaccinated with vaccine-or-test deadline approaching
The district adopted a policy in October requiring that all students ages 12 and older be fully vaccinated by Jan. 3 or get tested weekly. The policy is designed as an “on-ramp” to California’s vaccine mandate, which is expected to take effect July 1 once the FDA fully approves the COVID-19 vaccine.
With a vaccine-or-test deadline approaching in January, the count of Berkeley Unified students over 12 years old who are vaccinated against COVID-19 hasn’t budged, the number hovering around 80% since September.

District spokesperson Trish McDermott said the number of vaccinated students has likely “ticked upward,” as not all vaccinations have yet been reported to BUSD.
The deadline won’t affect in-person enrollment next semester, but unvaccinated students will be required to get tested. Currently, students can opt in to surveillance testing; about 84% of students have chosen to do so.
Racial disparities in vaccination rates are stark in Berkeley. At the high school, 91% of white and Asian students are fully vaccinated, compared with 54% of Black students and 43% of multi-ethnic students, according to data shared by the district Sept. 22.
In an effort to increase vaccine access, BUSD has held vaccine clinics at Berkley High and Berkeley Technology Academy, the district’s continuation school; has involved student leaders in a vaccination campaign; and has partnered with LifeLong Medical to provide vaccine education at community events. In December, the district plans to reach out to families of unvaccinated students, according to McDermott. All this is in anticipation of the vaccine mandate expected to hit next school year.
Dr. Rhoads, who is also the founding director of Umoja Health Partners, which works with community organizations in the Bay Area to fight COVID-19 in the Black community, praised the district’s effort to involve community members in a dialogue about the vaccine.
“I love campaigns like this because I really think we can make a difference just by opening up the dialogue, but it also requires us to be very humble about what we do and don’t know about this virus,” said Rhoads, adding that the results of such campaigns may not be immediate, but can have a positive effect in the long run.
Children between 5 and 11 years old have more time to get vaccinated or get tested weekly, per board policy. For them, the vaccine-or-test rule won’t kick in until March, four months after the FDA approved the vaccine for emergency use in that age group. Already, 69% of Berkeley kids in that age group have received one dose of the vaccine, nearly five times the state average of 14%.
Among BUSD staff, 92% are vaccinated against COVID-19. The remaining 8% already have to get tested weekly.
A handful of school districts have already enacted a vaccine mandate, including Oakland Unified and Los Angeles Unified, where 44,000 students missed the first vaccine deadline and risk being moved to an online independent study program.