Wavebreakmedia/iStockBy DR. DELARAM J. TAGHIPOUR, ABC News

(NEW YORK) -- The initial closure of kindergarten through 12th grade (K-12) worldwide was a decisive measure to curtail the global pandemic.

In the United States, school closings have impacted approximately 56.6 million students and their families. Globally, the shutdown has affected nearly 1.3 billion students, or just over 70% of the world’s student population.

The effects of school closures were felt far beyond the quality of education; families who lean on schools for meals, Wi-Fi, special education and other resources have suffered.

“The heartbreaking reality is that the students whose families are disproportionately impacted by the health-related impact of COVID are the same students who are most at risk academically and emotionally," said Jackie Peng, staff development teacher for Montgomery County Public Schools in Maryland.

The Senate on Wednesday will hold a hearing on the safest way to reopen K-12 schools in the United States.

With pressure mounting to reopen schools across the country, the Centers for Disease Control and Prevention has released new guidance to help schools plan, prepare and respond based on the level of community transmission and presence of COVID-19 cases, underscoring that all decisions should be made collaboratively with local health officials.

But with the science of COVID-19 transmission still an area of active research, reopening schools is risky. Although children seem to be less susceptible to severe illness, it’s too soon to declare they are "less capable" than adults to transmit COVID-19.

And the risks associated with reopening will differ for each community.

“It depends on where in the United States you are, what is the status of infections in the region you're in,” National Institute of Allergy and Infectious Diseases Director Dr. Anthony S. Fauci said Tuesday during a Q&A with JAMA editor Howard Bauchner. “If you’re in an area that has a considerable degree [of cases] with active ongoing infection, you might have to make a tough decision. It may be either delay or do modified schooling.”

There are a number of ways to schedule students to minimize risk. One is to split the students into two groups and have them either come for half a day or every other day. Though potentially safer, this option cuts down their overall time in school by 50%.

Another option could be putting students in cohorts. The students would be placed in the same classes and lunch periods to minimize exposure to other groups throughout the day. For younger age groups, this may be staying in one room for all lessons.

Virtual learning remains the safest option and it's possible virtual learning could be fine-tuned to be more effective. Some have proposed a "hybrid model" in which there is a combination of distance and in-person learning that is more accommodating for families who need to send children to school and those who wish to keep kids at home.

Until now, the spread of COVID-19 has been mitigated by stay-at-home orders, social distancing, mask or face covers, handwashing and respiratory hygiene, none of which are particularly easy for younger children to follow.

Rojia Banaei, director of a Montessori school in Ashburn, Virginia, cautions that younger children may need much more flexibility than older kids do. “Some of these children are way too young to understand why they have to keep a mask on for an entire day," she said. “It is going to take away from their focus.”

Banaei is also concerned about the mental health impact.

"If children over 2 are required to wear masks or not hug their friends for example, enforcing those rules may cause distress and add to fears and feelings of insecurity," she noted.

Reopening schools is a priority, but Tom Scott, executive director of the Massachusetts Association of School Superintendents, told ABC News there are real concerns about whether teachers and students will be willing to return.

“You have to think about it from the standpoint of our population of teachers who may be in the more vulnerable age category," he said. "The number of educators who perhaps have some sort of a health compromised condition, or that live in homes where that also may be part of their equation that they have to work with. The other obvious concern is the number of teachers who perhaps don’t want to take any risks and say maybe it’s time for me to retire.”

Added Peng: “The bottom line is learning doesn't happen in environments where students and teachers do not feel safe. Brain education research tells us that safety is a precondition to the brain's ability to learn.”

She suggests that “teachers must be engaged in discussions about plans to reopen and be at the table with public health experts.”

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