As the school moves away from 2-day in-person learning split into two cohorts, other important pillars of safety remain in place – and in the case of testing and ventilation, opportunities for improvement continue to surface.

Cohort merger begins as other safety measures prioritized

Safe in-person learning is doubling for many students, but the emphasis remains on 'safe.'

March 23, 2021

After a year of the continuous rising and falling of COVID-19 cases, immense research done by the world’s most decorated doctors and scientists and more than a year removed from the initial shut down of schools, students have begun to attend school in a more familiar way again.

The Public Schools of Brookline (PSB) have begun to allow students to attend school in-person four days a week with different roll-out days depending on grade level. Thus far, only the limited number of students in Cohort A have been attending school in-person four days a week at the high school. In the coming months, plans are in place to allow more students this option as administrators and committee members work to find ways to safely accommodate all students.

Many have been impatient to take this major step because of the concerns around the impact online learning has had on students. According to High Focus Centers, a resource for outpatient treatment programs regarding mental health, learning online has been a struggle for many, and has led to increased rates of stress, anxiety and depression amongst students, along with social isolation and decreased ability to process information being taught. Members of government, both town and national, have stressed the importance of getting children to go back to school in order to maximize their learning potential and avoid missing a crucial part of their development, both inside and outside of the classroom.

As the town begins to take a step forward to an in-person learning environment, there are five pillars of safety that come into play: cohorting and contact tracing, physical distancing, masks and personal protective equipment (PPE), ventilation and testing. As we have begun to move away from cohorting, the focus on ventilation, PPE, safe distance and testing has continued to show efficacy in keeping the schools safe for students and staff. According to David Gacioch, co-chair of Expert Advisory Panel 4: Public Health, Safety and Logistics, the district is well positioned to make this shift.

Cohorting and Contact Tracing

Cohorting has not been a large focus at the high school throughout hybrid learning, though it is recognized as an effective strategy to prevent outbreaks of COVID-19. When dividing students into multiple smaller cohorts, schools are often able to decrease the number of potential close contacts of any given student, therefore preventing large outbreaks.

Many districts have split grades into many small cohorts to minimize close contact amongst students, though the high school did not utilize this strategy. However, it did divide into two large and distinct cohorts: Monday-Tuesday (MT) and Thursday-Friday (RF).

Assistant Head of School Hal Mason said that grades 10-12 were assigned classrooms in different sections of the high school based on grade level in order to minimize the spread across grades. For example, senior classrooms are typically on the fourth floor, and sophomores are typically on the first floor on the Welland road side of the 115 campus.

According to Medical Director of Payment & Care Delivery Innovation at MassHealth, Instructor in Medicine at Harvard Medical School Lakshman Swamy, the major flaw in cohorting tactics at the high school has been the shift in focus and intention.

“Cohorting was being used to prevent huge outbreaks, and now cohorting is more to make contact tracing easier, which is very different,” Swamy said.

Mason also said that it is nearly impossible to find a group of students at the high school who share an identical or semi-identical schedule, meaning creating smaller cohorts is not feasible. He also recognized that that is not what high school should be like, and that the high school experience must include interacting with and learning with a variety of different students.

Because of the enhanced safety measures that have been implemented, the town has decided the high school is ready to move away from cohorting, regardless of how this may create more work for the school’s contact tracers, though Brookline has excelled in contact tracing thus far.

“I think it’s perfectly reasonable for a teacher to see lots and lots of students, as long as those protections are in place for that teacher, and as long as they’re still able to largely maintain distance and wear face masks,” Swamy said.

Gacioch agreed that the high school is ready to move away from cohorting.

“In terms of actual prevention of people becoming infected, {cohorting is} probably not as important at this point, and we should be focusing more on doing a really good job with masks and other PPE, keeping up our game on ventilation and those will do that work,” Gacioch said.

Currently, classmates or people that were interacting masked and distanced are not considered close contacts of someone who contracts COVID-19. Mason affirmed that there is no plan to change this protocol due to the low rate of in-school transmission.

Contact tracing has been carefully and successfully executed by school nurses and will continue this way. Nurses have been conducting rigorous and very specific interviews with students who test positive in order to identify all close contacts. Due to the low case count, Mason said this type of contact tracing is working very well.


Data regarding distancing is constantly evolving, but members of Panel 4 are confident that PSB can begin to move away from a strict distance of six feet at all times, and towards three to six feet during masked times with reliance on strong ventilation.

“We have better and better data now that the difference between three and six foot distancing really does not make any appreciable difference in safety profile when people are masked,” Gacioch said.

A relaxation of distancing policies will aid in solving one of the biggest problems in the high school: space. Mason said he has already run into difficulties accommodating larger classes of in-person students in classrooms at 115 Greenough street, and said that crowding and spacing is his biggest concern right now. At Old Lincoln School (OLS), the classrooms are even smaller, which has barred freshmen students from beginning four-day learning thus far. With a standard of three to six feet instead of a strict six foot rule, Mason said that he can arrange and accommodate a lot more students to attend school in person.

A clear distancing protocol and statement is still being worked out, but last week the district decided that a minimum distance of three feet was safe given the other precautions. As more students return to school full-time, the district appears to be headed towards this reduced distance to allow for larger class sizes.

“It seems like {less distancing} is where it seems like we’re heading towards, but that’s still being worked out by the district,” said Mason.

Members of Panel 4 have walked through the high school building with Mason to give their advice about next steps in terms of mapping out safe and appropriate places for students to learn. They also answered questions from the staff, especially in regards to distancing.

Masks and PPE

There is no doubt that masks work, but the question arises of which masks are the most effective. According to Swamy, it is not imperative to have KN95 masks, let alone N95 masks. The most important element of a mask is its fit.

“We want everyone to be wearing a mask that, number one, is well fitted. It’s far less important what kind of mask it is, but it’s really important that it’s well-fitted, even if you’re wearing an N95,” Swamy said. “If an N95 is leaking, it’s not a very good mask. It’s really much more about a good seal across your whole nose and mouth than it is about the filtration of the mask itself.”

The use of more advanced filtration masks would be to help people feel safer as opposed to really mitigating the spread, but as Swamy said, a feeling of safety is still important. $30,000 has been committed by community members to PSB to allow for more enhanced PPE, but these funds have yet to be directed.

Swamy said that the district and schools need to consider what factors are the most important in regards to safety before money and resources are spent.

“I don’t want the school to be in a position where they’re going to be committed to spending a lot more resources that they don’t have on something that really doesn’t add that much safety,” Swamy said.

One of the biggest challenges of in-person learning is unmasked times, which at the high school is only lunch, but at the K-8s there is also an allotted snack time during the day. The high school has access to large spaces, such as the auditorium, and there is less concern about students breaking rules. It is still paramount that there is supervision of students during unmasked times, as Swamy said that there is a natural tendency to do things wrong. Unmasked times represent one of the radical differences between in-person learning at the high school versus the K-8 schools, where students eat supervised in their respective classrooms.

According to Gacioch, there are three safe and low-risk options for unmasked times that the high school should aim to follow. In order of preference: to eat outside and try to keep a six foot distance, to maintain a six foot distance inside in a well ventilated space for a limited duration, or to maintain a three to six foot distance inside a well-ventilated space with physical droplet barriers for a limited amount of time.

Though these are all considered to be safe options, the consensus is to push to stay outside.

“The answer is outside. The answer is always outside. And the question is, why can’t we? We should all be asking ourselves over and over again, is it really that the weather is so bad that we can’t be outside and eat? Because it’s such a benefit,” Swamy said.

Gacioch also emphasized the importance of duration and frequency when it comes to unmasked times.

“If we’re able to get people outside two or three out of five days during lunchtime, every one of those times that you can do it outside rather than inside makes a difference in terms of further lowering risk,” Gacioch said.

Mason affirmed that in the coming weeks students can expect to be outside for lunch unless there are extreme weather circumstances.

“Now that the weather’s changed, that’s going to help a lot because we’re just going to push kids outside here, and there {at OLS} we’ll be pushing kids outside,” Mason said.

In the event of extreme weather conditions, Mason said that the high school will utilize both the auditorium and the cafeteria to ensure low numbers of unmasked students in each of these indoor spaces.


Ventilation is an area where the high school, and the town of Brookline have focused much of their attention. The current five air changes per hour in rooms at the high school meet the standard for “excellent airflow” according to a Harvard study for classrooms at full capacity.

Every classroom has a designated maximum capacity, and the standards in use for ventilation are based around a classroom at full capacity. PSB never sees a full capacity classroom even in a normal year. Thus, increasing the number of students in each classroom, even by a large amount, does not diminish safety nor affect the quality and efficacy of the ventilation system.

Nonetheless, PSB has decided to tweak ventilation to make sure all the spaces that will have to be used in the coming weeks meet this standard of excellence.

The ventilation system is one of the driving forces of the low rates of in-school transmission in Brookline. All the air exchanges and the increased filtration allow for a relaxing of some of the other protocols, namely those that pertain to social distancing and unmasked times, as we move to a four day in-person learning environment.


One of the newest additions to the COVID-19 safety measures has been the pooled testing program, which was developed by the Massachusetts Department of Elementary and Secondary School Education (DESE) and adapted for Brookline. According to Mason, this has proven to be a great strategy during a time like now, when the community case count in Brookline is low. The low positive test rate of these tests has also allowed increased confidence in protocols.

“{Pooled testing} lets Brookline say, ‘look at the things that we’ve done. We’re proving that they work,’” Swamy said. “It really ensures that the measures we’re already using are safe over and over again.”

The timing of the implementation of this pooled testing program is crucial to maintaining a sense of safety during four day in-person learning.

“Pooled testing is well-timed in the sense that it’s going to give us a few weeks of baseline data as we continue to move forward into more in-person schooling, and then will allow us to keep monitoring the situation to make sure nothing noticeably changes once we do move towards more in-person learning,” Gacioch said.

Although this program has given the town and school important data, work is being done to improve the program and make it more accurate and convenient. Due to the nature of pooled testing, there is always the possibility that you will have to take a second test if someone in your pool tests positive. Oftentimes, this hassle draws people away from participating in pooled testing, even though it is free of charge. According to Swamy, one of the goals set has been to make the pools smaller, in the hopes of improving accuracy and increasing participation.

Mason said that staff use of this program has been significantly higher than student use, and as more students begin to come to school fully in-person, the school is aiming to better promote and publicize the program for students’ own safety.

Mason also said that pooled testing could potentially be useful in stopping the spread of a quick spreading variant.

“Let’s say one of the variants comes and starts going through the town, the quickest way we would learn about that is through pool testing. Pooled testing would give us a really quick handle of ‘Oh, look, here’s this group of 10 students, and now we need to test each one of those, and then we’ll know is it just one kid?’” Mason said.

Due to the strong efficacy of this program, the BSC has committed to extending this program through at least May 7.


As Swamy said, one important thing to remember is that risk exists on a spectrum. As Brookline moves forward in returning to some form of post COVID-19 life, it is imperative that everyone understands and recognizes risks and listens to the data being presented.

After immense research from a variety of well-versed doctors and scientists in the community, many agree that as a town, we are ready to take this next step. In-school transmission remains low, and learning in-person has been proven to be vital to the development of students.

“We are not seeing evidence of transmission here or in other schools, and school settings do not seem to be any active vector of disease transmission,” Mason said.

Gacioch said that it is paramount to understand that no risk is ever zero, and that we will never achieve perfection. The conservative approach that the town has followed has allowed room to make mistakes and learn from them.

“We’ve got a lot of margin built in for error here,” Gacioch said. “Everybody can take a little breath and say, even if it wasn’t perfect yesterday, or it wasn’t perfect last week, we’re still pretty safe.”

The Sagamore • Copyright 2022 • FLEX WordPress Theme by SNOLog in


Comments (1)

All comments are reviewed by Sagamore staff before being published. To read our complete policy, see our policies underneath the About tab.
All The Sagamore Picks Reader Picks Sort: Newest

Your email address will not be published. Required fields are marked *

  • L

    Laurie LaskyMar 28, 2021 at 8:51 am

    Thank you for this outstanding piece of journalism.