Everything You Need to Know About Schools, Students and COVID Right Now


In states where schools open earlier that they do here in Washington State, the beginning of the school year has seen an immediate and substantial surge in COVID infections among school children. Some schools have been forced to return to distance learning less than a week into what was to be a year of in-person learning.

Districts are scrambling, parents are frightened, and COVID is sending children to the hospital at rates far higher than before. Will the same happen here, or are we better prepared than they appear to be in Hawaii, Arizona, Florida, Alabama, Missouri and the other states which are failing to contain the Delta variant right out of the gate? 

To answer this question, I’ve queried a number of districts across the state, reviewed state guidelines, and tracked Delta’s sobering disruption of what was to have been a summer of “putting COVID behind us.” Thanks to the Delta variant, COVID is once again squarely in front of us. This time, however, those on the front lines are less likely to be senior citizens, and much more likely to be K-12 students, who make up a large share of those still unvaccinated.

Delta appears to spread very rapidly among children, and the surge in serious cases is likely to lead to more deaths and cases of MIS-C among children as well. MIS-C stands for Multi-Inflammatory Syndrome—Children. It’s rare but dangerous if not recognized and treated very quickly. COVID infection can cause it. Of greatest concern, the surge in pediatric infections could lead to more cases of pediatric Long COVID.

It is hard to quantify yet the scale of the risk of these three bad outcomes, but even a relatively low rate of each, given the sheer number of unvaccinated children (~70 million), would create a substantial health crisis. Long COVID in particular has the potential to inflict long-running impairments, and it clearly happens to children as well as adults.

Best guesses at prevalence suggest that 1-4% of kids who get COVID will end up with Long COVID, and some of those cases may be permanent, or nearly so.  Given that cognitive impairment is a common component of Long COVID, parents in particular should pay close attention to it. Until now it has been under most people’s radar.

Due to Delta’s extreme infectiousness and Long COVID’s slow and subtle development in each person, Long COVID among children could become a crisis that unfolds before we realize that it’s happening, leaving many children with long-running brain fog, exhaustion, pain, or other symptoms. Since vaccines are already available for children ages 12 and up, and vaccines are likely to become available for children ages 5-11 this fall, it would be tragic to inflict a wave of bad health outcomes on our children just before vaccine protection is able to sharply reduce the risk.

What makes Delta so dangerous? First and foremost, it is dangerous because of how quickly and efficiently it spreads. Compared to earlier variants, Delta becomes infectious much faster after establishing itself in a new person—it can spread just 2-3 days after the infection begins, instead of 5-6 days with earlier variants. This is so fast that it becomes infectious 18-72 hours before testing is likely to find it. Delta’s R0 is thought to be between 5 and 9—that’s the number of people each person will infect once they become sick (before protections are taken into account).

That’s up in chicken pox or even measles territory. Earlier COVID variants are thought to have R0 values between 2 and 2.5. Delta creates a viral load in the upper respiratory tract over 1,000 times greater than earlier variants, and this is true for a significant proportion of vaccinated people as well as the unvaccinated.

The immune systems of vaccinated people kick in and suppress the viral load after about the 6th day, reducing transmission potential more rapidly, but because Delta becomes infectious so quickly, it has already had a pretty good chance to spread from vaccinated people before it is suppressed. Vaccines may only reduce transmission by 50% or less.

Vaccinated people are still very substantially protected from serious illness and death, but their protection from infection is significantly less than it was before Delta arrived. You may recall hearing that the mRNA vaccines were originally about 95% effective, meaning that you were 95% less likely to develop symptomatic illness after exposure than if you had not been vaccinated. Put another way, you were 20 times less likely to get sick.

Against Delta, protection against infection has been estimated to be 55-85%. This is one reason why we are hearing about breakthrough infections. These infections are still much less likely to lead to hospitalization and death, but many people still experience them as a serious bout of feeling unwell. An 85% level of protection means you would be about 7 times less likely to get sick than an unvaccinated person. Still good, but not as good as 20 times less.  55% effectiveness means you are about half as likely to get sick. Much better than nothing (and you’re much less likely to die), but not nearly as reassuring as 95% was.

Delta’s impact is also amplified by human nature. We let our guard down too soon: masking and social distancing went by the wayside in America earlier this summer, inviting Delta to have maximum impact. With all its advantages, Delta has quickly taken over as the dominant variant in the US, accounting for over 95% of all new infections.

What can parents do to minimize the risk that their children will catch Delta COVID? The first thing, of course, is to be sure that everyone in their households that is eligible for vaccination is fully vaccinated. Even somewhat battered by Delta, the vaccines are the strongest protective tool we have, and getting vaccination levels to the highest possible level is more important than ever.

The second thing parents can do is to become as active as necessary to improve the antiviral performance of their children’s schools. This is an uncomfortable step for many—few of us would enjoy grilling our child’s very decent and caring teacher about her school’s ventilation practices. Is it necessary? Are the schools falling short of achievable best practices? In many cases, yes they are, so yes the awkward grilling is necessary.

Photo by Mat Napo on Unsplash

In Washington, our K-12 schools have prepared themselves for the improving pandemic situation they reasonably hoped they would face, rather than the tougher reality which Delta and growing awareness of the risk of Long COVID are forcing on them. Delta’s stunning impacts on rates of infection, hospitalization and death only began ramping up sharply in the past six weeks.

In an institution as complex as the public education system in the state of Washington (260 school districts, 2400 schools, multiple state agencies), six weeks in the summer is a blink of an eye when it comes to specifying and implementing sweeping changes in institutional behavior. Washington’s Department of Health prepared very thoughtful and reasonably thorough guidelines for the return to in-person learning, and for most schools simply complying with those guidelines as best they can is their entire COVID readiness policy.

Unfortunately, Delta has blindsided those guidelines and unless schools up their games very quickly, Washington may end up in the same situation as the states that have opened ahead of it, with crash closings of schools, mad scrambles to reactivate remote learning programs, too many sick kids, and an ample supply of outraged parents.

Moreover, the degree of risk that Long COVID represents has been under-appreciated until recently: many people assumed that it was basically fine if lots of kids got infected, since the infections among kids were typically mild or asymptomatic, and very few children died of COVID. The threat of Long COVID, which is a consequence of infection rather than severity, changes that equation just as Delta makes it harder to prevent high rates of infection.

Washington’s state government has done two important things right. The first is the recent requirement that all school staff—anyone with student contact—must be vaccinated. Shockingly, Washington is the first state in the country to take this step. Given that most kids who catch COVID in schools appear to catch it from adults, vaccinating the adults to create a safer bubble around the kids seems like a basic and obvious step.

Most teachers, I should note, are already vaccinated—90% according to The New York Times. In the age of Delta, there is no “herd immunity” available by vaccinating only a percentage of the population with the current vaccines. Even with 100% vaccinated, the virus will survive, but will do far less harm. Hence the mandate.

The second thing Washington has done right is mandate masks for everyone in school buildings. Masks work best when everyone in a group is wearing them. Hence, a policy requiring masking is more effective than a flexible policy which results in a mix of masked and unmasked people in a group. Group masking works to lower transmission by 50-75%.

Mandates make masking the social norm for kids and their parents and take the burden off individual schools and districts to make policy. With a largely unvaccinated population of school children and a virus capable of breaking through even amongst the vaccinated, every layer of protection plays an important role, and masking is one of the most important layers.

To calculate how masking and vaccination work together, take the 85% efficacy of the vaccine mentioned above, and then add 50-75% of the remaining 15%. By adding masking to vaccination, your overall efficacy climbs to 92-96%. Masking pretty much makes up for the decline in vaccine efficacy against Delta and gets you back close to 20-fold reduction in risk.



To minimize the frequency and scale of Delta COVID outbreaks in K-12 schools across the state, here’s what every school should do (and DOH guidelines should support) to build on the state’s mandated teacher vaccinations and universal masking.

  1. VACCINATIONS: Having school staff vaccinated is a great first step, but not enough. Schools should also require all eligible children to be vaccinated, promote it, and make it easy to achieve. This is not impossible: the Catholic schools in New York, which serve a larger student population than Seattle’s public schools, require student vaccination, and the New York City public schools require student athlete vaccination.

    Nationwide, just 33% of 12-15-year-olds and 43% of 16-17-year-olds are vaccinated. A majority of parents of 5-11-year-olds do not intend to have their children vaccinated unless the schools require it. The schools should require it, as they do with so many other vaccines. Vaccines may be approved for 5 to 11-year-olds as early as October. Meanwhile, the FDA has issued its full approval (not just Emergency Use Authorization) for the Pfizer vaccines this week. This could make it easier for school districts and the state to mandate student vaccination. It also will allow doctors to administer “off label” vaccinations: that is, they will be able to vaccinate children under 12 at their own discretion.

    Schools should also have teachers urge the parents of their students to have every eligible person in their household vaccinated. Children spend many hours a day at home, and an unvaccinated older sibling or cousin is a threat. Teachers may have influence where others do not. Last but not least, as school staff become eligible for boosters, they should get them and urge parents to do the same. The boosters are likely to significantly restore and extend the power of the vaccines.

Current Situation: Washington’s DOH’s guidance had no vaccination requirements for schools until the Governor announced mandated vaccination for school staff. DOH has been a primary campaigner for voluntary vaccination in general across the state.

  1. VENTILATION: COVID is an aerosol spreader: very tiny droplets float in the air like invisible smoke, and the concentrations build up to dangerous levels in confined spaces unless the air is frequently replaced or purified. A typical school classroom replaces its air 2.6 times/hour. Some are much worse than this. A minimum recommended ACH (Air Changes per Hour) under COVID conditions is 5.0. This would be better for kids and teachers in other ways as well. How can schools achieve this? The San Diego Unified School District, which is about double Seattle’s size, got there this way:
    • They started with their HVAC system and upgraded all possible filters to MERV-13 standards, which do an excellent job of filtering out virus-carrying aerosols. For systems too old and weak to muscle air through MERV-13s, they upgraded to the next best thing, MERV-11s. They checked all filter installations and taped up leaks around the filters. They set the system for maximum outside air use, and they run the system full blast from two hours before the school day begins until two hours after it ends. They disabled demand-sensitive controllers that might turn the system off and on in individual rooms and reduce flow. They established protocols for checking and changing the filters.
    • They tested the airflow in every room, simulating the presence of a full class of students and staff. They used dry ice, smoldering candles, and other visible measures to see the airflow.
    • They installed CO2 monitors and particulate monitors in every room. CO2 is a good proxy for exhaled air, the source of infectious aerosols. Fresh outside air has about 400 PPM (Parts Per Million) of CO2. Air being exhaled by breathing humans has about 40,000 PPM. Hence, CO2 monitors tell you how much exhaled air is still in the room.
    • In every room that didn’t meet the standard of at least 5.0 ACH, they added portable HEPA air purifiers. These fan/filter devices remove aerosols enough to compensate for sub-standard ACH if they are properly sized for the space. The district ordered 10,000 of them. They put one in every restroom, among other places.
    • They maximized opportunities to teach outdoors, eat outdoors, study outdoors. Being in San Diego helped. In Washington, perhaps schools should do what restaurants have done, and add rain shelter and radiant heaters in outside spaces to make them more useful in imperfect weather.

Current Situation: DOH’s ventilation guidance is directionally and qualitatively correct: it favors MERV-13 filters and maximum outside air, speaks approvingly of HEPA air filters, etc. It does not, however, specify a quantitative standard such as minimum 5.0 ACH in every room, it does not require or promote CO2 monitors, and it does not specify room-by-room assessment of airflow. Schools can be “in compliance” and yet far from safe enough.

  1. MASKING: Masking and Ventilation are sibling solutions: both strive to reduce the amount of virus (the “viral load”) that reaches people’s upper airways over time. A school with hurricane-grade ventilation which made its inside air as good at diluting and dispersing suspended virus particles as outside air could in theory do away with masking requirements. Conversely, perfectly-masked individuals should be safe even in poorly-ventilated spaces.

    In the real world, there are few hurricane-grade ventilation systems and few perfectly-fitted masks, so we double up. A masking mandate is only as effective as its participants make it. The quality of the masks used, the fit, and the continuousness of compliance all matter. Masks work by filtering, not straining. The spaces between the mask fibers are big enough for viruses to pass through, but the number and distribution of fibers make in likely that nearly every particle will stick to a fiber before passing out the other side.

    The “gold standard” N95 masks are not made in children’s sizes, but KN95 and KF94 masks are. A cloth mask over a surgical mask (those light blue ones) is an effective solution, as are some of the cloth masks with full width inserted filters. Some people have expressed concern that mask-wearing in schools will interfere with children’s linguistic or emotional development. The response from linguists and childhood development researchers is mostly reassuring—they see little actual risk for school-aged children wearing masks 6 or 7 hours a day.

    A big issue with masks in schools is lunch. The mask hasn’t been invented yet which can stop viruses while letting fish sticks through. The typically cacophonous school lunchroom is a great place for viral spread. There are several partial solutions. One is to push as much lunch-eating outside as possible. Another is to add more lunch periods in order to reduce the population density in the lunchroom at any one time and give the air in the room time to recover between periods. A third is to reconfigure tables and chairs to minimize close face-to-face eating. In any case where a lunchroom is used, over-the-top ventilation will help—enough to blow the ketchup off the french fries would be a useful standard.

Current Situation: The state mandates masking for everyone inside school buildings. The DOH guidelines clarify that this generally does not apply outside, and spells out certain other exceptions, including “a medical condition, mental health condition, developmental or cognitive condition, or disability.” San Diego Unified actually followed up every doctor’s letter asking for an exemption and disqualified 80% of them. If enough students show up with “notes from a doctor” to justify a mask exemption, Washington districts may need to do the same.

  1. TESTING, TRACING AND QUARANTINE: There will be cases of COVID in schools. In parts of the state where the virus is more prevalent in the community, it will be a more frequent visitor to the schools. The task facing schools is to keep cases from becoming outbreaks as much as possible. Delta, with its high R0 value and short turnaround between infection and reinfection, makes the task more challenging.

    The first line of defense is what’s called screening testing. This means testing everyone in the school frequently, to catch cases as soon as possible. Two solutions have emerged to reduce the onerousness and cost of this task. One is the use of “instant” tests—paper strips that give pretty accurate results really fast and pretty cheap. Anyone with positive results from these tests is quarantined while more rigorous PCR tests are run.

    The second hack is sometimes called pool testing: the nasal swabs from 25 people at a time are pooled for a single PCR test. If this multi-booger test comes back negative, the whole group is cleared. If it comes back positive, individuals within the group are quarantined and tested. When a person tests positive, its important to quickly trace his or her contacts, test them too, and quarantine them as needed.

Current Situation: DOH does not require screening testing except for students in certain high-contact sports, but it recommends screening testing when community transmission is at “moderate, substantial, or high levels,” as defined by the CDC.

  1. QUARANTINED STUDENT SUPPORT: Delta will ensure that, on any given day, schools are likely to have a fair number of students not in class. Some will be too sick to study, but many will be quarantined at home, infectious but not unwell, or perhaps just quarantined until their infectiousness is determined. As difficult as it is, remote learning or other ways to help these students keep up will be important. Many districts across the state abandoned remote or hybrid learning with relief after the state mandated that all schools must provide in-person learning, but now many will be faced with de facto hybrid situations: 80% of the kids in class with 20% quarantined at home, for example. As before, this will be harder on some students and parents than others, and burdensome for teachers, but best efforts are necessary.

Current Situation: DOH offers detailed quarantine guidance, but one aspect of it seems out of date. It says that people who have been vaccinated and are then in close contact with an infected person don’t need to quarantine. This policy does not seem to take into account the fact that the Delta variant appears able to infect the nasal passages of a vaccinated person and make that person fully infectious for a period of several days even if the person’s immune system successfully controls it. This exemption was recently added and should be reconsidered.

  1. OUTBREAK PLANNING: Best efforts to contain cases are not likely to work perfectly, meaning that schools will be contending with outbreaks this year. What protocols will they follow to contain the outbreaks, balancing the costs and benefits of their decisions? Delta and greater awareness of Long COVID puts pressure on schools to make decisions very quickly. “Let’s wait another day to see how much worse this gets” is almost always a bad choice. The stress on parents, staff, and students of adopting outbreak control measures is high, but an uncontrolled Delta outbreak could quickly infect a whole building full of students. Districts without sensible and well-articulated outbreak plans are going to look like Afghanistan Exit Reenactors.

Current Situation: DOH’s discussion of outbreaks is primarily concerned with the legal reporting requirements, not what steps schools should take if an outbreak (defined as two or more unrelated cases) occurs. There’s also detailed guidance about how to handle each case of a suspected new infection that occurs during the school day, but not about how to organize an outbreak plan. Given the state’s strong position in favor of in-person education, it’s not surprising that DOH avoids discussing scenarios in which closing schools could become an option.


What can parents do?

  1. Be sure your vaccine-eligible children and every other eligible person in your household is vaccinated. Get boosters as indicated.
  2. If your child is under 12, talk to your doctor about vaccination now that the FDA has given vaccines final approval, which permit doctors to decide to vaccinate children under 12. Otherwise, if your child is under 12, get him or her vaccinated as soon as the FDA issues an EUA for that age group.
  3. Invest in masks your children are most likely to wear properly which also meet filtration standards, and then fiddle with the fit until it’s right.
  4. Communicate your concerns clearly and urgently. Here are points of input available to parents:
    • Your children’s teachers and school principal. They have limited sway over policy, but a lot of control of implementation, and a lot of influence on policy if enough of them make enough noise up the ladder to the district administration and school board. You are their constituents, and they truly care about your children, but they don’t go out on limbs without support.
    • Your school board. School boards are the point of attack for anti-vaccine and anti-mask activists. Without strong input from parents who favor vaccines, masks, and other sensible policies to protect children, school board members can be swayed by the noise from Antiva and Antima enough to dissuade them from taking prompt action in the right direction.
    • The press. Washington’s Department of Health has weekly sessions where they take reporters’ questions on live group calls. If the reporters start asking smarter, more detailed questions, DOH hears it immediately, and other reporters hear it. Most larger school districts also have dedicated press relations staff, which provide a quick conduit to decision-makers if reporters start asking new questions about stuff like HEPA purifiers and screening testing.

Public policymakers and parents alike are in a difficult spot right now, trying to make decisions when there’s a lot of uncertainty about very consequential facts. What will Delta do over the next six months? When will vaccines for children under 12 become available?  Will schools be able to slow the rate of infections among their students? What are the odds that serious Long COVID will afflict my child?

A few months ago, optimism was in the air: millions of adults were getting vaccinated daily, data was showing that COVID was very rarely fatal to children, vaccines were on the way for children 12 and up, people were emerging from their bunkers, and the prospects for a “return to normal” seemed within reach. The situation today is worse: the adult vaccination campaign ran into determined resistance, Long COVID is emerging as a serious threat to children, children 12+ have been very slow to get vaccinated, and Delta has pushed “return to normal” off the table for now.

Over time, we will settle into an endemic relationship with this virus, where most people will have significant resistance to infection and especially to serious disease, the death rate will be much lower (though not as low as the flu), vaccinations at some appropriate rate will routine, and we can concentrate on saving the planet, saving democracy, and other worthy objectives. We’ll get there, but first we have to finish dealing with this pandemic, which has yet to show much willingness to slip into any sort of equilibrium with us.

Tom Corddry
Tom Corddry
Tom is a writer and aspiring flâneur who today provides creative services to mostly technology-centered clients. He led the Encarta team at Microsoft and, long ago, put KZAM radio on the air.


  1. I suggest that readers of this thorough and well-researched article urgently send it around to friends and parents.

  2. I’ve seen several well-regarded experts in the past few days argue that US schools should NOT offer indoor instruction to unvaccinated students, period, even if this means returning to all of the hardships of remote learning. They argument they make is that Delta is proving itself capable of blowing past every defense except vaccination, and that Long COVID among children appears to be too prevalent to be ignored–perhaps 4% of cases, which is about one kid per classroom.


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