Florida schools: mask dispute continues 2:54
(CNN) -
An unvaccinated elementary school teacher who removed her mask to read to her students ended up infecting more than half of them last May, and they in turn infected other students, family members and members of the community, California public health authorities reported Friday.
It's an example of how easy it is to undermine efforts to protect children too young to be vaccinated, said Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention (CDC, for its acronym in English).
The teacher came to work despite having COVID-19 symptoms and then removed her mask to read to the young students, a Marin County Public Health team reported in the CDC's weekly report on deaths and illness.
The professor assumed the symptoms indicated allergies, not an infection, the researchers found.
7 Ways to Support Kids' Immune Systems as They Go Back to School and Await the Covid-19 Vaccine
In the classroom of 22 students, 12 were infected, including eight of the 10 students in the first two rows.
And this despite the multiple measures designed to prevent the transmission of the virus.
"The school required teachers and students to wear masks while indoors; interviews with parents of infected students suggested that student adherence to mask use and distancing guidelines, according to According to the CDC recommendations, it was high in the class. However, the teacher was reported to remove the mask at times when reading aloud in class, "the report said.
"Throughout this period, all the desks were separated by two meters," he added.
"All classrooms had portable high-efficiency particulate air filters and the doors and windows remained open."
advertising
How does the delta variant affect children?
1:42
It was not enough to protect the children.
Eventually 27 people, including the teacher, became infected.
None became seriously ill and all recovered.
The cases that were analyzed corresponded to the delta variant of the coronavirus, although the researchers said they were not necessarily able to analyze all the people who could have been infected in the outbreak.
The CDC singled out the case as an example of how schools must follow all recommendations if they want to protect students and staff.
"The introduction of the virus into the classroom by a teacher who worked in the school, while she was symptomatic and was not vaccinated, and who removed her mask when reading aloud to a class, led to cases within the classroom, throughout the school and among students' families and community staff, "Walensky said at a COVID-19 briefing at the White House on Friday.
"We know how to protect our children at school. We have the tools."
The CDC guide for schools lists vaccination as the # 1 way to protect everyone.
"Vaccination is the main public health prevention strategy to end the covid-19 pandemic. Promoting vaccination can help schools safely resume in-person learning, as well as extracurricular activities and sports," he said .
Children under the age of 12 cannot be vaccinated, and the CDC says it is important that the adults around them get vaccinated to protect them.
Dr. Lisa Santora, the county's deputy health director, said officials there had been urging teachers to get vaccinated since January, but many had not.
"We saw firsthand that it wasn't the children who were going to make the teachers sick. It was going to be the other way around," Santora told CNN.
Santora said Marin County had hosted "Super Saturday" events to encourage teachers and staff to get vaccinated, but some teachers remain unvaccinated.
"Adults are underestimating their risk of hospitalization when they decide not to get vaccinated," he told CNN.
Santora said that 90% of the people in hospitals with COVID-19 in the county at this time are not vaccinated, and many are between 30 and 50 years old.
The outbreak at the elementary school was a warning to the county that the delta variant was going to make it harder to prevent outbreaks, he said.
"Some of the adults who were part of the outbreak, who were parents of school children, were vaccinated. That was another indication for us that the delta variant was different," he said.
What we've learned from schools reopening: masks work
"Among the five infected adults, one of the parents and the teacher were not vaccinated; the others were fully vaccinated," the report says.
"The vaccinated adults and one unvaccinated adult had symptoms of fever, chills, cough, headache, and loss of smell. No other school staff reported becoming ill."
The county was able to carry out an intense contact tracing operation that provided a good picture of what happened.
Apparently, several children were infected during a pajama party, and some of the infected teacher's class appear to have infected their siblings.
Testing the majority of exposed children was key, because many of them never developed symptoms.
"The school did the right thing with all of its mitigation strategies," Santora said.
"I think if it wasn't [the variant] delta, I don't think we would have seen this."
Nonetheless, the CDC concluded that schools can safely open for face-to-face classes if they are careful.
Los Angeles County officials studied cases that occurred in their schools between September and March.
They counted 463 cases among students at the time that could be linked to an exhibition at school, and 3,927 among staff who returned to be in person.
This is a much lower case rate than in the general community during the same period, they reported.
"In schools with safety protocols for prevention and containment, child and adolescent case rates were 3.4 times lower during peak winter compared to community-level rates," they wrote.
"This analysis reflects transmission patterns before the more transmissible SARS-CoV-2 variant B.1.617.2 (delta) became predominant in the United States. A multiplex prevention strategy, including the use of of masks, physical distancing, testing and, more recently, vaccinating children and adolescents 12 years of age and older, will continue to be critical in reducing transmission as more students return to classrooms, "they added.
"These findings from a large and diverse county present preliminary evidence that schools provided a relatively safe environment during the 2020-21 school year."
Opening of schools