Experts have stressed the importance of in-person learning for students' development and access to essential services. On the other hand, Covid-19 case, hospitalization and death rates remain high across the nation.
In an effort to strike the right balance, schools have adopted varying approaches that include in-person learning, online learning and a hybrid of the two.
In a paper published in the Journal of the American Medical Association Tuesday, CDC researchers noted that the kind of spread seen in crowded offices and long-term care facilities has not been reported in schools. In-school transmission has occurred, but the researchers said there is little evidence that it contributed meaningfully to increased community transmission.
"Committing today to policies that prevent SARS-CoV-2 transmission in communities and in schools will help ensure the future social and academic welfare of all students and their education," the researchers wrote in the JAMA paper.
Two new studies from the CDC published Tuesday in agency's Morbidity and Mortality Weekly Report demonstrate that with the right precautions, children can return to school safely.
Triple-layer face masks and no high-contact sports
In the first study, researchers looked at data on 17 K-12 schools in rural Wood County, Wisconsin, that conducted in-person learning last fall. They found lower Covid-19 case rates than in the community at large, and few cases of in-school transmission.
Of 5,530 students and staff, 191 tested positive for Covid-19. The researchers found that Covid-19 case rates in schools were 37% lower than in the surrounding community.
Contact tracing and investigation determined that seven of those 191 cases -- 3.7%, all among students -- were contracted in school. Three of the seven students who tested positive were from one elementary school class.
The schools did not conduct routine Covid-19 screening, but they implemented mitigation measures.
For example, students were each provided with three to five double- or triple-layer cloth masks. Masks were required in schools, and statewide, more than 92% of students of all age groups wore them.
Cohorts of 11 to 20 students from the same grade level met for classes and lunch indoors, where students were often seated next to the same person. Cohorts were asked not to mix, and the researchers found no in-school transmission between different cohorts.
Staff were told to mask, social distance and limit time in shared indoor spaces. If a student was out of school with Covid-19 symptoms, their siblings were also told to stay home.
When a student or staff member tested positive for the virus, school officials used interviews to identify close contacts -- anyone who was within 6 feet of the person for longer than 15 minutes over the course of 24 hours. Those close contacts were required to quarantine at home, and if they developed symptoms during that time, officials investigated whether in-school spread was the cause.
The team says their findings suggest that even with varying positivity rates in the community, students are not necessarily at increased risk for the virus if they attend in-person classes. In fact, they say that being in a monitored environment such as the classroom may increase adherence to public health measures.
Extracurricular activities, such as indoor sports, may be another story, according to a separate CDC report published Tuesday.
Two Florida high school wrestling matches became superspreader events in December when 54 of the 130 attendees -- wrestlers, coaches and referees -- were tested for Covid-19, and 38 were positive. Among 91 close contacts of infected people, 43% tested positive for the virus. One contact, who was over the age of 50, died.
It is not possible to maintain physical distancing in the high-contact sport, and the American Academy of Pediatrics advises against mask wearing while wrestling because it poses a choking hazard.
After calculating the amount of time everyone involved had to quarantine and isolate, the researchers estimated there were 1,700 in-person school days lost due to the outbreak -- a number they say would likely have been higher if the outbreak had not occurred so close to the end of the semester.
"Outbreaks among athletes participating in high contact sports can impact in-person learning for all students and increase risk for secondary in-school and community transmission with potentially severe outcomes including death," the researchers wrote.
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