Here are the risk-levels of contracting COVID-19 in schools, according to Gerba and Stephanie A. N. Silvera, epidemiologist and professor at Montclair State University. (This first appeared in Advance Media.)

Walking in the hallway – Moderate to higher risk

• Hallways typically don’t have windows so ventilation is poor. Plus they tend to be densely packed with people, which increases risks.
• “Requiring face coverings to be worn while walking in the hallway would reduce the risk as would reducing the number of students in the hallways at any given time,” Silvera said.
• Reopening rules dictate that floors and sidewalks should have tape and signs to help with social distancing in common areas and hallways.

Eating lunch in the cafeteria – Higher risk

• Like any indoor dining, this is considered a high risk activity because of ventilation issues, there are a lot of surfaces that will be touched and students can’t wear face coverings while they’re diving into a sandwich.
• “Lunch rooms are one of the germiest areas in most schools,” Gerba said, adding that students should be encouraged to eat in their classrooms.
• As part of the new rules, schools are looking at staggering lunch times to allow for social distancing and disinfecting. Self-service and buffet-style food service will not be allowed.

Using a locker room – High risk

• Locker rooms typically don’t have windows, so, like any indoor activity, the risk is higher, especially if everyone is not wearing a face covering, SIlvera said.
• “The size of the locker room is also important,” she said. “Smaller locker rooms will make spatial distancing more difficult.”
• Under New Jersey’s reopening plans, schools are advised to keep locker rooms closed for gym and they won’t be available for high school sports.

Riding a school bus – Moderate risk

• “The risk can be reduced by creating distance between the children by having one child per row or skipping rows,” Silvera said. “Having the windows open to increase ventilation would further reduce risk as would requiring face coverings.”
• “Some buses here are used three times in the morning and afternoon to take children to elementary, middle and high schools,” Gerba said. “They’re going to have to try to disinfect between loads.”
• Under the reopening plans, districts are being asked to try to create space between kids on buses and if they can’t, to install physical barriers between rows.

Sitting in a classroom (elementary school) -Moderate to high risk

• “This is going to be largely dependent on two factors: the number of children in the room, which impacts the ability to distance, and ventilation,” Silvera said.
• “If the students can be spaced at least 6′ apart and the windows can be kept open and the air from outside can be circulated in, then the risk would be lower,” she said. “Having both students and teachers wear face coverings would further reduce the risk.”

Sitting in different classrooms throughout the day (middle and high school) – Higher risk

• “This increases risk because it requires groups of students to travel in the hallways and it increases the number of students touching shared surfaces without adequate time to sanitize those surfaces,” Silvera said. “A better option, though not feasible for all classes, would be to have the teachers move between rooms.”
• “Either way, having teachers exposed to more students throughout the day increases their risk and since adults generally have a higher risk profile both for becoming infected and having more adverse outcomes, this is a far more challenging scenario,” Silvera said.

Using a restroom – Low/moderate risk

• “The key is to limit the number of people in the bathroom at any given time and to require face coverings because these are smaller spaces,” SIlvera said. “Frequent cleanings are important as well.”
• “Coronavirus is present in urine and feces and when you flush, it becomes airborne,” Gerba said. ”So ventilation is important.”
• Hand dryers also should not be used because they can blow bacteria around the room, he said.
• The state’s guidelines on reopening suggest limiting how many people can be in the bathroom, having trash cans with foot pedals, and leaving the exterior bathroom doors open to eliminate touching.

Visiting the library – Moderate to high risk

• As with any indoor activity, risk is higher and because libraries don’t have windows to protect the materials from moisture/mold, absent high quality ventilation systems, these would be higher risk,” Silvera said. “As always spatial distancing and wearing of face coverings mitigates this risk.”
• “The tables will need to be disinfected between classes,” Gerba said. “And the number of students at each table should be limited.”

Outdoor recess – Low to moderate risk

• If spatial distancing can be maintained, this is a lower risk activity and, it is important to provide students with opportunities for healthy physical activity, Silvera said.
• Playgrounds should be closed for the time being, Gerba said, because all those hands touching the same surfaces could spread germs quickly. If playgrounds are used, students should be marched right in to wash their hands. “Correct handwashing has to be first thing kids learn when they go back to school,” he said.
• Reopening guidelines don’t require schools to close playgrounds. Instead, they’re being asked to stagger the times they are used and disinfect frequently.

Gym class inside the gymnasium – High risk

• “This is higher risk because of the indoor setting coupled with increased force of exhalation due to physical activity and the inability to realistically wear face coverings,” Silvera said. “For this reason, I think physical education classes, which are positive and important, should be done outdoors.”
• State guidelines don’t go that far. They require markers or ways to delineate social distancing and limiting the use of equipment or at least disinfecting after every use if it has to be shared.

Computer (Higher risk) or science lab (Low to moderate risk)-

• “Science labs could potentially be safer if they are following CDC guidelines for labs, including use of face coverings and spatial distancing, then this could be possible, particularly given that a lot of these lab activities cannot be done at home,” Silvera said.
• “Computer labs are much like libraries. While they have air conditioning to protect the computers, the issue that needs to be addressed is how much transfer of external/internal air is being exchanged,” she said.
• Guidelines by the state only suggest that schools be given disinfecting wipes to use on surfaces that will be touched commonly, like keyboards and computer mice.