Unvaccinated Teacher Infected Half of Students in Classroom: CDC Study

MONDAY, Aug. 30, 2021 (Healthday News) -- A case study from California may fuel further debate about vaccine mandates in schools as students return to classrooms.

It occurred in Marin County, Calif., in May and involved an unvaccinated elementary school teacher infected with the highly contagious Delta variant who then infected half of the students in a classroom, triggering an outbreak that affected a total of 26 people, the U.S. Centers for Disease Control and Prevention reported.

The teacher first experienced symptoms on May 19, but worked for two days before getting tested. During this time, the teacher read aloud without a mask to a class of 24 students, despite rules requiring both teachers and students to wear masks indoors, the report stated.

All the students were too young for vaccination, which has been authorized only for people ages 12 and older.

On May 23, the teacher reported testing positive for infection with the coronavirus. Over the next several days, 12 of the students also tested positive.

"I thought I respected its contagiousness," Dr. Lisa Santora, deputy health officer at the Marin Health and Human Services and an author of the report, said of the Delta variant. But the virus' efficiency in overtaking the classroom "surprised and humbled" her, she told The New York Times.

Everyone in the front row of the classroom tested positive, tapering to 80 percent in the first two rows, the report found.

It was one of three new CDC studies focusing on schools or children. Another report concluded that several infection prevention measures at schools can make them low-risk settings for students, but it was conducted before the surge driven by the highly contagious Delta variant.

The third study showed that COVID-19 vaccination rates for 12- to 17-year-olds are highly uneven across the country, the Times reported.

All three reports were published Aug. 27 in the CDC publication Morbidity and Mortality Weekly Report.

New York City and some other school districts have announced vaccine mandates for teachers and staff, and others may do the same now that the Pfizer vaccine has received full approval from the U.S. Food and Drug Administration.

"The most important thing we can do to protect schoolchildren, particularly those too young to be vaccinated, is to make sure the adults in their lives, including teachers and school staff, are vaccinated," Jennifer Nuzzo, an epidemiologist at Johns Hopkins University who was not involved in the studies, told the Times.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on guidelines for returning to the classroom.