How the Delta Variant Infiltrated an Elementary Faculty Classroom

An unvaccinated elementary school teacher infected with the highly contagious Delta variant spread the virus to half of the students in a classroom, triggering an outbreak that eventually infected 26 people, according to a new report from the Centers for Disease Control and Prevention .

The unusually detailed study that is taking place in the wake of the reopening of school districts across the country certainly seems to fuel the debate about vaccination regulations in schools. A handful of school districts, including New York City, have already announced vaccination requirements for teachers and staff.

Others may follow suit now that the Food and Drug Administration gives the Pfizer BioNTech vaccine full approval.

“The most important thing we can do to protect school children, especially those who are too young to be vaccinated, is to make sure the adults in their lives, including teachers and school staff, are vaccinated,” said Jennifer Nuzzo, epidemiologist from Johns Hopkins University, which was not part of the report.

The study was one of three new CDC reports that focused on schools or children. In another study, the researchers found further evidence that schools can be low-risk environments when they combine several precautionary measures. But this research was done before the delta variant spread.

A third report focused on vaccination rates for adolescents. Half of all 12 to 17-year-olds have received at least one dose of a coronavirus vaccine, the White House said on Friday. However, the new study found that vaccination rates for this age group varied widely across the country.

Together, the studies show how much scientists have learned about protecting children in schools – and how much remains uncertain after the Delta variant arrives.

The classroom outbreak occurred in Marin County, California in May. Neither the school nor the staff and students involved were identified.

The teacher first showed symptoms on May 19, but worked for two days before being tested. During this time, the teacher read aloud to a class of 24 students, unmasked, despite regulations that require both teachers and students to wear masks indoors.

All of the students were too young for a vaccination, which is only approved for people aged 12 and over.

On May 23, the teacher reported that she had tested positive for coronavirus infection. In the next few days, 12 of the students also tested positive.

“I thought I respect his contagion,” said Dr. Lisa Santora, assistant health officer at Marin Health and Human Services and author of the report, on the Delta variant. But his efficiency in overtaking the classroom “surprised and humiliated” her.

In the classroom, the infection rates roughly corresponded to the seating plan. Everyone in the front row tested positive and decreased to 80 percent on the first two rows.

In the back three rows, only 28 percent of students tested positive. “If the teacher doesn’t have a mask, go to the back of the class,” said Edward Traver, an infectious disease fellow at the University of Maryland Medical Center, in a Twitter message.


Aug. 27, 2021, 11:20 p.m. ET

Six students from another class at the school also tested positive for the virus. The cases spread from school to the community: at least eight parents and siblings of the infected students, three of whom were fully vaccinated, were also infected.

State health researchers sequenced samples of the virus from many of the positive cases and found that all were infected with the Delta variant. Samples from at least 10 students in two grades were genetically indistinguishable. The results suggested that the cases in both grades were from the same outbreak.

The outbreak was likely fueled by both Delta’s high infectivity and the fact that the teacher did not follow recommended safety precautions, the researchers said.

“We need to make sure that both schools and individuals work together to keep our safety,” said Tracy Lam-Hine, epidemiologist at Marin County Health and Human Services and author of the new report. “It can’t just be one or the other.”

In other parts of the country the toll on the community could have been even higher. Marin County has the highest vaccination rate in California. The report found that 72 percent of eligible people in the surrounding community were fully vaccinated, suggesting that high rates may have prevented further transmission.

In another new study, researchers focused on the case numbers in Los Angeles County, where some students and teachers attended school in person last year while others did so remotely.

Understand US vaccination and mask requirements

    • Vaccination rules. On August 23, the Food and Drug Administration fully approved Pfizer-BioNTech’s coronavirus vaccine for people aged 16 and over, paving the way for increased mandates in both the public and private sectors. Private companies are increasingly demanding vaccines for employees. Such mandates are legally permissible and have been confirmed in legal challenges.
    • Mask rules. The Centers for Disease Control and Prevention in July recommended that all Americans, regardless of vaccination status, wear masks in public places indoors in areas with outbreaks, reversing the guidelines offered in May. See where the CDC guidelines would apply and where states have implemented their own mask guidelines. The battle over masks is controversial in some states, with some local leaders defying state bans.
    • College and Universities. More than 400 colleges and universities require a vaccination against Covid-19. Almost all of them are in states that voted for President Biden.
    • schools. Both California and New York City have introduced vaccine mandates for educational staff. A survey published in August found that many American parents of school-age children are against mandatory vaccines for students but are more likely to support masking requirements for students, teachers and staff who are not vaccinated.
    • Hospitals and medical centers. Many hospitals and large health systems require their employees to have a Covid-19 vaccine, due to rising case numbers due to the Delta variant and persistently low vaccination rates in their communities, even within their workforce.
    • New York City. Proof of vaccination is required by workers and customers for indoor dining, gyms, performances, and other indoor situations, though enforcement doesn’t begin until September 13. Teachers and other educational workers in the city’s vast school system are required to have at least one vaccine dose by September 27, with no weekly testing option. City hospital staff must also be vaccinated or have weekly tests. Similar rules apply to employees in New York State.
    • At the federal level. The Pentagon announced that it would make coronavirus vaccinations compulsory for the country’s 1.3 million active soldiers “by mid-September at the latest. President Biden announced that all civil federal employees would need to be vaccinated against the coronavirus or undergo regular tests, social distancing, mask requirements and travel restrictions.

Schools opened to face-to-face learning have had to take a variety of precautionary measures, including symptom screening, masking, physical distancing, and contact tracing. For most of the period between September and March – and especially during the spike in winter – the number of cases in schools for both teachers and students was lower than in the county as a whole.

The results are in line with previous studies that have shown that the case numbers in schools are often lower than in the surrounding community when schools combine several protective measures.

“The school is in many ways a safe place for young people because it is so structured and supervised,” said Dr. Santora, who is personally having a 9 and an 11 year old return to school this fall.

But the studies on school mitigation, including the Los Angeles report, were conducted before the delta variant spread. The variant is about twice as transmissible as the original version of the virus and now accounts for almost all infections in the USA.

Whether the same precautionary measures will keep the variant in check in schools this year remains uncertain, and many schools have opened without the safety measures recommended by health experts.

Siobhan Flynn, who teaches first grade at a public charter school in the greater Washington area, is concerned about classes starting Monday. The school Ms. Flynn works at uses a layered approach to protection that includes a mask mandate, socially distant desks, and randomized tests for students.

“Children have to be in school, but I just wish more money and planning had gone into opening schools safely,” Ms. Flynn said. “Many would feel much safer if all the staff were vaccinated.”

Vaccination rates have risen in the past few weeks as Delta continues to cause spikes in cases, hospitalizations and deaths nationwide. But parents were concerned about sending young children back to school if they couldn’t be vaccinated.

The FDA first approved the vaccines for 12 to 15 year olds in May, and by July 31, more than a third of them had received at least one vaccination, according to a third CDC report. More than half of 16-17 year olds eligible for the vaccine months earlier had received at least one dose.

But vaccination rates vary widely across the country. In Mississippi, only 11 percent of teenagers were fully vaccinated, compared with 60 percent in Vermont, the researchers found.

Dr. Westyn Branch-Elliman, an infectious disease researcher at Harvard Medical School, said in an email that she hoped schools would become “more involved in promoting vaccine uptake for all eligible in the school community by setting up vaccination clinics “. in schools to improve access and break down barriers. “

Clinical trials of the vaccines in young children are ongoing. Pfizer said the results should be in by September.

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