Students wearing masks in school. Photo by KURT DESPLENTER/BELGA MAG/AFP via Getty Images

An unvaccinated primary school teacher in Marin County, California spread COVID-19 to 26 other people, including 50% of her classroom, after spending two days sick with the coronavirus at school while not always being masked, according to a new Centers for Disease Control and Prevention report.

The report, published Friday, highlights how vital it is to both vaccinate and mask elementary school teachers to protect children under 12 who cannot get vaccinated yet.

“We know how to protect our kids in school. We have the tools,” CDC Director Rochelle Walensky said Friday, discussing the report during a White House COVID-19 briefing.

The teacher in question “was both symptomatic and unvaccinated” Walensky said, and “was unmasked when reading aloud to the class,” where her students were all too young to be vaccinated.

Her actions resulted in 12 COVID-19 cases among the class of 24 kids, along with six other illnesses at the K-8 school, and eight parents and siblings infected.

The investigation used viral genome sequencing to determine the cases were all likely related. All of the COVID-19 cases sequenced in the outbreak were classified as the Delta variant, which is about twice as contagious as other versions of the virus.

No one was hospitalized.

Sitting closer to the teacher upped the odds that kids got sick, even with masks

To get a better idea of how the virus swirled around class, the CDC drew up a map of the classroom, showing the prevention measures that had been taken.

Students’ desks were spaced apart six feet, windows and doors were left open to promote good ventilation, and an air filter was installed at the head of the class. Kids’ adherence to CDC guidelines on both masking and distancing in school was “high” in class, according to interviews the CDC conducted with parents.

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But with an unmasked, unvaccinated teacher at the helm, none of that mattered so much.

She continued teaching for two days while symptomatic, starting on May 19, with her symptoms worsening from initial congestion and fatigue that she wrote off as allergies, into a cough, fever, and headache.

It did seem, however, that sitting further away from the sick teacher helped protect students, which makes sense when you consider how the coronavirus travels from person to person through the air when sick people talk or shout.

“The attack rate in the two rows seated closest to the teacher’s desk was 80% (8 of 10) and was 21% (3 of 14) in the three back rows,” the CDC report said.

The finding underscores what other experts have been saying for a while now – more adults need to be vaccinated in order to protect everyone from the Delta variant.

“6 feet is not magical,” Mike Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota said Thursday on his podcast, stressing that he thinks the CDC guidelines don’t yet go far enough to prevent the spread of the more contagious Delta variant.

“We can make [school] safer, and we have to do that,” Osterholm said. “The first thing we do is we use our vaccines.”

Read the original article on Business Insider