An unvaccinated teacher was responsible for an outbreak in Marin in May that infected 26 others, according to a report released last week by the Centers for Disease Control and Prevention. The teacher, one of two unvaccinated staffers at a school identified in news reports as Our Lady of Loretto School in Novato, worked for two days after becoming symptomatic. During that time, the teacher read aloud to the classroom while unmasked, spreading the virus to 12 out of 24 kids in the class. The report kept the school’s name confidential, but said it serves 205 students from pre-kindergarten through eighth grade. The C.D.C. scientists stressed the importance of both masking and vaccinating teachers as schools reopen. By October, all of California’s teachers need to be vaccinated or submit to weekly testing. At Bolinas-Stinson Union School, all of the teachers are vaccinated, superintendent John Carroll said, but at Lagunitas School, one teacher remains unvaccinated. Shoreline Unified School District superintendent Adam Jennings said 98 percent of the district’s classroom teachers are vaccinated. School districts cannot publicly disclose the vaccination status of individual employees.