An unvaccinated California elementary school teacher, who went to work while sick with COVID-19, ended up infecting 26 people, including half of the class, according to a report.
The unidentified teacher, who worked in Marin County north of San Francisco, developed symptoms on May 19 but continued working for two days before getting a test that was positive for the coronavirus, according to the report published Friday by the US Centers for Disease Control and Prevention.
The teacher first attributed the symptoms to allergies and later developed a cough, fever, and headache, according to Marin County health officials and local experts.
The unidentified teacher read aloud to the class of 24 without wearing a mask — despite school requirements about masking indoors, the report said.
An investigation of the outbreak found that 8 of 10 students seated in the two rows closest to the teacher tested positive for the coronavirus, as did four students in the back of the class.
Six students in a different grade at the school, which serves those in prekindergarten through eighth grade, also tested positive as did eight parents and siblings of students.
All of the infected students at school were too young to have been vaccinated.
Among the five infected adults, one parent and the teacher were unvaccinated, the CDC said. Genome sequencing on 18 specimens from those infected showed the cases were all tied to the highly transmissible COVID-19 Delta variant.
The teacher was one of two unvaccinated staffers at the school.
“This outbreak of COVID-19 that originated with an unvaccinated teacher highlights the importance of vaccinating school staff members who are in close indoor contact with children ineligible for vaccination as schools reopen,” the CDC report said.
The school appears be the parochial Our Lady of Loretto in Novato, Calif., which had been the linked to an outbreak in May, according to The Mercury News.
The Archdiocese of San Francisco said in a statement to the newspaper that the incident referred to in earlier news reports and in the CDC report “was an isolated circumstance and has been addressed internally.”