It took only a few days for the American Federation of Teachers, their second-largest union, to say “not so fast” to the CDC’s recommendation for opening schools by reducing pupils' distance from six to three feet. What is the science behind their concerns?
Randy Weingarten, President of the AFT, sent a letter to the Director of the CDC and the Secretary of Education. She made two arguments. Concerning the scientific basis for the CDC’s recommendations, discussed here, she noted that the schools had implemented a variety of mitigation strategies, especially around upgraded HVAC (ventilation) systems, that were not addressed and might well impact the findings. The researchers had noted this as well. Her second argument was that the studies were not conducted in high-density, poor schools, so the results might not be generalizable. To my mind, this is a weaker but still valid objection.
She ends by suggesting more studies in those high-density, poor schools so that better planning can be done for summer and fall instruction. The CDC’s cited study took four months of data, so it is wishful thinking that such information will be available for summer school, maybe for the fall. As to her other concerns, she cited her own science, fittingly titled, New CDC Guidelines to Reopen Schools Could be Dangerous, written by the Institute for New Economic Thinking. (INET) 
The “Other” Study
The INET report is an opinion piece grounded in scientific studies. It begins by pointing out that many individuals infected with COVID-19 are asymptomatic, particularly children. This makes the certainty of transmission studies problematic. Unless you identify all the asymptomatic cases, it is tough to identify actual risk. Of course, uncounted asymptomatic children would lower the risk of transmission as they are added to the transmission rates' denominator.
They point to a series of studies that show higher transmission rates during in-class learning for students K-12, especially to teachers and parents. There are two difficulties with these studies. First, most lump, bin is the formal term, K-12 together, so elementary school kids with lower transmissions and teens with higher transmissions have higher transmissions are grouped together. The CDC recommendations were only for elementary and middle school. The second difficulty is that none of the studies control where the teachers and parents were throughout the day – their infections may be due to exposure in other situations, not from the child.
The report’s citations also indicate that teachers are at greater risk of infection than other workers. Compared to teachers doing remote learning, in-class instruction was associated with a 43% increase in infections, comparable to a 46% increase in infections for other essential services such as police and fire and rescue. The risk of healthcare workers, arguably the most exposed, was 23%. The CDC’s new guidelines again recommend the personal protection equipment for healthcare workers for teachers, basically a mask and a six-foot social distance from their pupils.
Having covered studies, they get to the crux of their concerns. Ventilation
“Most critically, while the authors were correct in saying that there is little difference in risk relative to seating distance, they drew exactly the wrong conclusion from the distance data.”
The report indicates that COVID-19 is an airborne disease. While multi-layer interventions are necessary to mitigate risk successfully, ventilation is the key in reducing viral loads, exposure, and infections. The use of masks, another CDC recommendation, also reduces viral loads, but no studies compare the two approaches, and the INET article does not address this at all. Their solution is “wholesale improvement in ventilation, filtering, and HVAC systems,” which will take time.”
Here is a real-world policy decision. We know remote learning has been disastrous; we know teachers are fearful of returning. There is “science” to be brought to bear on both sides of the issue. Choosing the right course of action is not “following science” as much as it is selecting the scientific data you “wish” to follow. In the meantime, vaccines are increasingly available. According to the National Education Association, the largest teacher’s union, only 11% of their membership is vaccine-hesitant, and 87% are willing to return to work if fully vaccinated. Let’s get that done. It can be accomplished far more quickly than retrofitting HVAC systems, which should be done anyway.
 “Founded in the wake of the financial crisis in 2009, the Institute for New Economic Thinking (INET) is a nonpartisan, nonprofit organization devoted to developing and sharing the ideas that can repair our broken economy and create a more equal, prosperous, and just society.”