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Like every other parent with a school-age child, I want schools to reopen in the fall — including the one I’m attending.

On the best of days, my son can be described as “spirited.” After four months of being cared for by his grandparents, he is practically feral. He needs the physical and social outlet that school provides, and I need the anatomy lab to reopen because human dissection is an irreplaceable part of my medical education.

But I am also an epidemiologist, and after reading the Centers for Disease Control and Prevention’s guidelines for school reopening and the various accompanying news coverage and think-pieces, I can’t convince myself that following its rules will keep my family — or yours — safe.


Why? Because the primary way Covid-19 is transmitted is through respiratory droplets that careen through the air, and yet the capricious nature of air circulation and the lack of filtration systems in our already underfunded public school systems is absent from the conversation.

Since New York state started reopening, I have received emails from my medical school’s working group about the plan to bring us back to campus. Its plan is to follow the basic script seen in school reopening strategies all over the country: frequently sanitized high-touch surfaces, 6-foot distances, unidirectional hallways, reduced capacity elevators and classrooms, health questionnaires, and contact-free temperature checks upon entry (more on that in a minute).


My school is not negligent, but like many other educational institutions, its efforts are dangerously misdirected. We are collectively engaging in what Derek Thompson describes in the Atlantic as “hygiene theater,” in which organizations looking to reopen focus intensively on arduous decontamination strategies to mitigate surface transmission — even though that is not the primary route for Covid-19 transmission, and some scientists argue that there is no direct evidence the virus spreads this way at all. I’d also like to add temperature checks to the hygiene theater playbill, as they too fail to successfully screen potential Covid-19 carriers, but have somehow made their way onto every screening list I’ve seen.

Why is this happening? The CDC is supposed to determine the national priorities for American health.

Of the eight bullet points in its “staff safety” section, four address surface transmission. The three bullet points dedicated to respiratory droplets warn people to stay 6 feet away from each other, cough into their elbows, and wear a mask.

The current CDC guidance about ventilation is as follows, “Ensure ventilation systems operate properly and increase circulation of outdoor air as much as possible, for example by opening windows and doors.” But if opening windows or doors increases the risk of asthma, or falling out the window, the guidelines go on to advise that they should be closed. That is all the guidance has to say. It does not mention air filtration, or the fact that we have pretty good data to suggest that without addressing air filtration and circulation, the 6-feet rule does not prevent transmission indoors.

Here are the things that caught my attention as an epidemiologist as schools played Tetris with classroom furniture and agonized over hybrid schedules.

On May 6, Erin Bromage, a microbiologist at the University of Massachusetts at Dartmouth, published a widely read article detailing the role of air circulation at three major indoor transmission events: a call center in South Korea, a restaurant in Guangzhou, China, and the infamous choir practice in Washington state. Each of these events taught us that transmission happens when you spend significant time indoors. Being 50 feet apart with “a low dose of the virus in the air, over a sustained period, was enough to cause infection and in some cases, death.” This happens because infectious particles from individuals are pushed by the ventilation system to the other side of the room. Bromage’s post appeared 127 days before the first day of school in New York City.

HEPA filters are able to effectively capture particles the size of SARS-CoV-2. The CDC currently recommends their use for this purpose in hospitals, but their capacity to prevent the spread of Covid-19 in other public buildings remains under-explored. Though the CDC has stayed silent on the use of HEPA filters outside hospitals, on May 25 a group of ENT doctors made the case for installing them in doctors’ offices where “aerosol generating procedures” are being performed, because of evidence they can help prevent the spread other infections such as SARS-CoV-1, measles, and influenza. That was published 108 days before the first day of school in New York City.

On May 27, a group of 36 scientists from around the world in a variety of fields penned an article in the journal Environment International titled, “How can airborne transmission of Covid-19 indoors be minimised?” As they wrote, “Here, in the face of such uncertainty, we argue that the benefits of an effective ventilation system, possibly enhanced by particle filtration and air disinfection, for contributing to an overall reduction in the indoor airborne infection risk, are obvious.” It’s obvious to me as well, and deserves to be our primary concern in reopening schools, far more urgently than distance or Lysol. That was 106 days before the first day of school in New York City.

McKinsey & Company reviewed research regarding airborne spread of SARS-CoV-2 and on July 9 posted an article suggesting possible upgrades to existing heating, ventilation, and air conditioning (HVAC) systems. A key recommended change was to increase the number of times HVAC systems exchange air per hour, which would push the infectious particles outside and prevent them from being blown across the room. This article appeared 63 days before the first day of school in New York City.

When I mentioned these possibilities to a friend who teaches in the New York City schools, she replied, “Don’t worry about our HVAC systems. They’re all broken.”

Instead of using limited time and funding to engage in hygiene theater, we should be investigating how to address ventilation. Or at the very least, be honest with the public about some institutions’ inability to make interior spaces safe.

As a result of months of misapplied focus on surface disinfection, the importance of air circulation and the potential use of filtration is missing from the national debate on school reopening. My son’s school and mine are both concerned with delivering our education safely. My son’s preschool director was worried sick about not being able to adequately decontaminate on a daily basis because she loves both the kids and her school.

It shouldn’t be her responsibility to research ventilation theory and filtration techniques and air flow patterns. It’s not my job as a medical student to Google these things trying to get enough information to decide what to do about my son’s school, and mine, starting imminently. And it’s not up to the administrators at my school, who I know have been working around the clock these last few months, to figure this out.

This is supposed to be done by the CDC. Here we are, about a month before public schools are supposed to begin, and the CDC is still failing to signal the crucial importance of addressing ventilation.

We need to include air circulation patterns and filtration options in the conversation. If we’re not willing or able to fund necessary upgrades to school ventilation systems, let’s admit that. Until we have that public discussion, I am not comfortable exposing my family to schools. Because if I can’t trust that the people making these decisions are reading the literature, how can I trust them with my family’s health?

Alexandra Feathers is an epidemiologist and first-year medical student at SUNY Downstate.

  • Xandra,

    You are correct. I have been trying to spread the message that our national conversation of COVID has omitted ‘mechanical means of prevention’ such as ventilation, air purification and UVC light to prevent the accumulation of ‘infected indoor air.’ After an initial YT video on that broader point, I uploaded one tailored to school re-openings called: Safer School Re-Openings During COVID – ‘It’s the Buildings Stupid’ which echoes your Op-Ed in greater detail. As a trial attorney and parent of young students in New York, I’ve contemplated legal action over the failure to address adequately ventilation/indoor air in both courts and schools. Feel free to contact me.

  • It is an appalling short-fall on the part of the CDC, to fail to stress the importance of air filtration. Likely this was orchestrated as purposeful omission as far too many schools can not make the necessary improvements in time for school re-starts. It’s an odd source for a Trump-ian thing: down-play danger, or don’t mention it, and just open up for a sense of normal. It will be false. Start the new case-counting ……..

  • Not to mention cruise ships which seem to offer optimal conditions for spread. Much circulation of air thru internal ducting systems- not adequately filtered or tested. Recent infections on a Norwegian line which had gone back into business.
    Obviously many variables- but I would not send a kid back into a school that had payed no attention to the matter

  • I wouldn’t send my kid back to school. There is no way these people who run the schools know what they’re doing. Also, the CDC lied to everyone in the beginning when they claimed that masks were ineffective so who can trust them? It was obvious that they were lying because Asian countries such as South Korea had everyone wearing masks. Also when South Korea tried to send kids back to school they had to close them due to outbreaks so maybe the kids weren’t being compliant/consistent with their mask wearing. Also we don’t know what kind of masks they were wearing. If they can’t keep the schools open in South Korea they won’t be able to keep them open in the U.S. We don’t even have good testing and contact tracing in N.Y., N.J. etc. The virus will spread like crazy.

    • j.denino57 – I feel your pain. I’m trying to get my school district to respond to a questionnaire (from in order to make a risk based decision on whether my children should go back to school. From their response (and non-response) I am not confident they are ready.

  • Merv 13 or higher filters catch nearly all the droplets and some aerosols. UVC lights in the duct can kill most of the virus. They both require more frequent maintenance. Setting roof HVAC for max fresh air and leaving fan on would work.

    • Thomas – The question is whether the schools are doing that. Maximum outside air and MERV 13 filters can be a very helpful element of this. However it isn’t everything – Air Change Rate (how often the air is removed from a room in an hour), proper wearing of masks, proper distancing, and much more all need to be present to truly affect risk. And, even then, the risk might be fine for some and not low enough for others – and each of us need to make that determination individually. Which is why using a risk based approach to understanding this is the way to go – see

  • Thank you for your realistic and pointed article. I believe you are absolutely correct. Ventilation is a key to help stop the spread of virus especially in schools. I also have made the decision to keep my child home and remove her from the high school band program due to the extreme avoidance to address aerosols and COVID-19 transmission indoors . We pay thousands to send her to private school, who want to open 5 days per week with 25 children in a classroom at 7 hour each day. My guess is if the schools followed measures about ventilation that are not outlined by the cdc guidelines they would not receive the millions in stimulus to open in person.

  • Consider yourself “woking” up. Do you really think the scientists at CDC don’t know airborne precautions are used for airborne illnesses, like COVID? Or that using PCR to “diagnose” viral load isn’t legit? It boosts the numbers, yes, so how is the death rate still 0.2%? Or that my 1990 Virology text book mentions chloroqine against coronaviruses? It’s not the virus we need to fear.

    • I currently work in a nurses office in a title 1 k-8 school, but my concern comes from 40 years of prior work in schools in several states, as a teacher as well as support staff. There have always been noteworthy problems with ventilation systems and usually inadequate funds allocated to really improve them. Now more than ever I think the subject needs attention.So I’m not sure I understand your response

    • You article brings up a very relevant point. Covid requires airborne precautions. I work in a hospital. Same precautions are used for TB, neg pressure rooms. But Why Isn’t the CDC talking about this? The scientists know about this. My point is that it is omitted purposefully. What could be their reason behind it? CDC wants a demand for vaccine, because they help develop them and then purchase the US supply and hospitals and others purchase vaccines from them. There is a bigger globalization plan some hope to usher in in conjunction with this. And some individuals are being sacrificed for the cause (thus far elderly). Consider you are 7x more likely to die in a car accident than from COVID. PCR can be used to amplify fragments. You may have breathed in a coronavirus sometime in your life, these fragments from old viruses are in your body, PCR picks it up and OH, you are positive! But you have no symptoms and you are not contagious. But it keeps the panic going. Are you catching on now?

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