This commentary is by Yves Dubief, father of fully vaccinated school-age children, and an associate professor of mechanical engineering at the University of Vermont studying the flow of aerosols between people within the context of Covid-19.
The Covid-19 Delta variant is spreading widely throughout our community. We currently have twice the level of community spread that should have triggered an indoor mask mandate under CDC guidelines.
Over 4.5 million U.S. children have contracted Covid-19 and the case rate is surging exponentially. The number of new hospital admissions of pediatric Covid-19 is at an all-time high for the past 12 months in the U.S. and increasing. There is a growing concern about lack of availability of pediatric ICU beds in many parts of the U.S.
This is the reality in which Vermont’s children are returning to school. In fall 2020, Vermont reopened its schools with a robust 41-page plan and only five cases. This year? Not so much.
The vulnerability of children to Covid often gets overlooked. While the risk of death for children is low, approximately 1% will end up in a hospital and as many as 10% will suffer from long Covid. Schools, while essential for a kid’s educational and emotional health, provide the perfect breeding ground for outbreaks, combining: crowds, indoors, prolonged exposure, and, in some cases, no masks (for schools without mandates or during lunch).
In a year, we have learned that the transmission of Covid is primarily airborne, spreading via aerosols in the breath of infectious people when breathing, speaking, coughing or sneezing. The best strategy is therefore 1) clean the air (ventilation/purification), 2) reduce the risk of inhalation and emission of aerosolized virus copies (masking) and 3) vaccination to reduce the population that can infect and be infected.
In the face of the virulence of the Delta variant, the CDC recommends universal indoor masking in areas of high community transmission, which includes all of Vermont. The American Academy of Pediatrics takes it a step further, recommending a layered approach for in-person learning, including universal masking.
Currently, Vermont’s leadership is ignoring these recommendations and the clear risk that widespread outbreaks present to our children and their hope of an uninterrupted school year. But it is not too late to enact statewide policies to protect our children and our community.
Given the case rate in Vermont, it is not a question of if Covid will appear in your child’s classroom; it’s a question of when. With minimal mitigation measures, we can assume each case will lead to six new infections, not to mention missed class time due to quarantining, illness, etc. If we want our schools to safely remain open, Vermont must do more.
Most experts, like this group of epidemiologists, aerosol specialists, pediatricians along with the AAP and CDC, recommend a layered approach that includes all of the following:
- Universal masking: Regardless of vaccination status, all members of the school community should wear a high-quality mask while indoors. Ideally masks should be well fitted N95, KN95 or KF94, or double masking (a surgical mask overlaid by a cloth mask). Why universal masking? Because a mask vastly reduces the number of aerosols emitted by infectious people and also reduces the number of aerosols inhaled. Appropriate masks for different ages can be found here.
- Ventilation/air purification: Since Covid-19 is airborne, we must clean the shared air we breathe indoors. If the airborne viral dose is low, the risk of infection for a masked child or adult is also low. This is why being outdoors poses a very small risk compared to crowded indoor spaces. For classrooms, ventilation should maximize the outdoor airflow with ideally six air changes per hour and MERV-13 filters for the building. If ventilation is poor, air purification using HEPA filters have been shown to significantly reduce aerosols. Ventilation and air purification can be combined for greater efficiency.
- Lunchroom management: The weak spot of most schools is the cafeteria — it doesn’t matter what you do in the classroom if you ignore what’s happening in the lunchroom. Speaking generates more aerosols than breathing and they quickly spread around the room. The louder the voices, the more aerosols produced and the farther they travel. Eat outside as much as the weather allows. When inside, schools must ramp up ventilation and air purification in the cafeteria. Use a staggered lunch plan to create physical space between children. Also, distance increases the probability of aerosols being sucked into ventilation and air purifiers airflows.
- Vaccination: Encouraging and improving the vaccination rate in the community is essential. However the evidence from Europe and Israel is clear — “vaccine alone” is not sufficient.
- Testing and tracing: Rapid identification is key to halt the spread. This includes contact tracing even for fully vaccinated individuals who absolutely can catch and spread the virus.
On their own, none of these mitigation approaches is sufficient. However, combined, they are highly effective at reducing spread and will vastly reduce risks of contamination in our schools.
My professional opinion is that we are not doing enough. Our state mask policies are not aligned with the best science available. Our contact tracing guidelines are not aligned with those recommended by the CDC. We have not done enough to educate all Vermonters about the importance of mask quality. Many schools don’t have enough understanding on how to mitigate aerosol spread in their classrooms and lunchrooms.
But remember that most school leaders and facility teams have been working overtime since last year to upgrade their ventilation, while also conducting contact tracing. I spoke with some school employees who are already dreading the long nights of contact tracing on top of trying to figure out the safest plan for this year in the absence of any state guidance.
As a parent, demand more from our state leaders. Seek out high-quality masks for yourself and your children. Ask about your school’s lunch plan. Advocate for our schools. Make sure all indoor spaces have good ventilation and air purification. Ask your school if and how you can help. You can offer to make these DIY air purifiers, for example.
We have a small window of time to keep our school kids, teachers and staff safe and it is closing quickly. Let’s help schools stay open for this entire year.