Schools no longer are advised to keep students 6 feet apart, federal health officials announced Friday — and a University of Utah study of elementary schools in Salt Lake County provided evidence that 3 feet was safe enough.
The findings have far-reaching implications for schools nationwide, as the U.S. Centers for Disease Control and Prevention relaxed coronavirus prevention guidelines that had called for 6 feet of space between desks. The precaution had prevented some schools from offering full-time, in-person instruction.
In Utah, 6 feet of spacing was impossible — and that made Granite School District a good study subject, said district spokesman Ben Horsley.
“You’re dealing with the largest class sizes in the nation,” he said.
Researchers from the U. identified 51 infected students and employees at 20 schools in Granite District, as well as one private school in Salt Lake County. To track the spread, researchers tested as many of those patients’ in-school contacts as they could — more than 700 people, or 70% of the patients’ contacts, said Adam Hersh, a U. professor of pediatric infectious diseases and lead researcher on the study.
If any of the patients’ contacts tested positive, researchers tested family members and performed detailed contact-tracing investigations to rule out other possible sources of exposure. In some cases, they also did genetic sequencing to confirm that both the source and the infected contact had the same strain of the virus.
Of those 735 people who had contact with an infected person at school, only five were believed to have caught the coronavirus that way.
That amounts to a “secondary attack rate” of less than 1%, Hersh said. “Overall we found very low rates of in-school transmission,” he said.
In four of those five cases, researchers learned of “obvious breakdowns in prevention strategies, including poor mask use,” Hersh said.
“This validates that these prevention efforts are working and that in-person learning can be done safely in elementary schools under these conditions,” Hersh said.
But most of those five cases also ended up spreading the coronavirus to family members, he added, “which reinforces the importance of limiting in-school spread.”
“Children in school do spread disease to their family,” said Dr. Andrew Pavia, division chief over pediatric infectious diseases at University Hospital.
Although the study looked at elementary schools only, researchers concluded that for middle and high schools, “in-person schooling can be safe when there’s a multilayered prevention strategy,” Pavia said — measures like masks, ventilation and diligent attention to symptoms so people stay home when they might be sick.
But the elementary schools in the study did not have many extracurricular activities underway, Pavia noted.
“It tells us a lot about the safety of the classroom, but not necessarily about all the activities that children are involved in throughout the school day,” Pavia said.
The study also doesn’t provide insights into other settings where 6 feet of distancing has been the norm. “I think it would be dangerous to extrapolate too far,” Pavia said. “Schools are a very controlled setting.”
The U. study aligns with findings of similar studies elsewhere in the country, Hersh said.
“All of these studies have arrived at the same conclusion, which is that there does not appear to be any difference in the transmission rate based on 3 feet or more up to, say, 6 feet — in the context of really aggressive adherence to all of the other mitigation and prevention strategies,” Hersh said. “If these students and teachers and staff members weren’t wearing masks, it would have been a totally different story.”
The revised recommendations represent a turn away from the 6-foot standard that has sharply limited how many students some schools can accommodate. Some places have had to remove desks, stagger scheduling and take other steps to keep children apart.
Three feet “gives school districts greater flexibility to have more students in for a prolonged period of time,” said Kevin Quinn, director of maintenance and facilities at Mundelein High School in suburban Chicago.
In recent months, schools in some states have been disregarding the CDC guidelines, using 3 feet as their standard. Studies of what happened in some of them helped sway the agency, said Greta Massetti, who leads the CDC’s community interventions task force.
While there is evidence of improved mental health and other benefits from in-person schooling, “we don’t really have the evidence that 6 feet is required in order to maintain low spread,” she said.
Also, younger children are less likely to get seriously ill from the coronavirus and don’t seem to spread it as much as adults do, and “that allows us that confidence that that 3 feet of physical distance is safe,” Massetti said.
The new guidance:
• Removes recommendations for plastic shields or other barriers between desks. “We don’t have a lot of evidence of their effectiveness” in preventing transmission, Massetti said.
• Advises at least 3 feet of space between desks in elementary schools, even in towns and cities where community spread is high, so long as students and teachers wear masks and take other precautions.
• Says spacing can also be 3 feet in middle and high schools, so long as there is not a high level of spread in the community. If there is, spacing should be at least 6 feet.
The CDC said 6 feet should still be maintained in common areas, such as school lobbies, and when masks can’t be worn, such as when eating.
Also, students should be kept 6 feet apart in situations where there are a lot of people talking, cheering or singing, all of which can expel droplets containing the coronavirus. That includes chorus practice, assemblies and sports events.
Teachers and other adults should continue to stay 6 feet from one another and from students, the CDC said.
The guidance change comes at a time when new, more contagious variants of the coronavirus are increasingly spreading. That means a continued emphasis on mask wearing and other such measures, Massetti said.
The National Education Association warned that the new recommendations could be “particularly challenging for large urban school districts and those that have not yet had access to the resources necessary to fully implement the very COVID-19 mitigation measures that the CDC says are essential to safe in-person instruction, no matter how far apart students in classrooms are.”
”For the sake of public trust and clarity, we urge the CDC to provide far more detail about the rationale for the change from six feet to three feet for students in classrooms, clearly and publicly account for differences in types of school environments, new virus variants, differences in mitigation compliance, and how study participants were tested for the virus,” NEA president Becky Pringle wrote in a statement.
But CDC Director Dr. Rochelle Walensky said the revised recommendations are an “evidence-based roadmap to help schools reopen safely, and remain open, for in-person instruction.”
“Safe in-person instruction gives our kids access to critical social and mental health services that prepare them for the future, in addition to the education they need to succeed,” she said in a statement.
Last year, the CDC advised that one way for schools to operate safely was by keeping children 6 feet apart, the same standard applied to workplaces and other settings.
In contrast, the World Health Organization suggested 1 meter — a little over 3 feet — was sufficient in schools. The American Academy of Pediatrics says desks should be 3 feet apart and “ideally” 6 feet.
The CDC guidance was problematic for many schools that traditionally had 25, 30 or more children per classroom in closely grouped desks. Some schools adopted complicated scheduling that might, for example, have half a class come to school on some days and the other half on other days.
The Ridley School District in suburban Philadelphia took steps like that to follow the 6-foot guideline after the CDC emphasized it last summer. But neighboring communities went with 3 feet, “and we’re not seeing the data really reflect a different spread rate,” said Lee Ann Wentzel, the district’s superintendent.
The district had already decided to shift to 3-foot distancing starting next month and invite all students to attend five days a week. But Wentzel said she was glad to hear of the change in CDC guidance because that will make it easier to explain and defend the district’s decision.
A recent study in Massachusetts looked at infections of students and staff members in schools that used the 3-foot standard and those that used the 6-foot one. It found no significant difference in infection rates.
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