New York State, the center of the worst coronavirus outbreak in the world four months ago, is now one of the few places in the country that may be able to safely reopen schools, several public health experts said after Gov. Andrew M. Cuomo gave districts permission to do so.
Mr. Cuomo announced Friday that public school districts across the state could hold in-person classes this fall, even as districts in many parts of the country where cases are still rising have abandoned the idea and will continue with remote learning.
In interviews, doctors, epidemiologists and other public health experts said that conditions were favorable throughout the state, including New York City, to bring children back — as long as safety precautions are in place. Some expressed concern that the effects of keeping students home were more worrisome.
As of Wednesday, fewer than 1 percent of Covid-19 tests statewide were positive, well below the 5 percent positivity threshold that both the Centers for Disease Control and Prevention and the World Health Organization have targeted as a safe standard for reopening schools.
In New York City, the positivity rate is just slightly higher than the state average, with 1 percent of tests coming back with positive results. Mayor Bill de Blasio has said schools in the city would not open if the metric rises above 3 percent. A report last month from Harvard’s Global Health Institute also recommended opening schools only when the daily infection rate is less than 3 percent.
“If there’s any city that should be opening in the entire country or at least trying to open, it should be New York City,” said Dr. Uché Blackstock, an urgent care physician in Brooklyn and founder of Advancing Health Equity, a health care advocacy group, who has children in the public schools.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University, said reopening the schools in New York was a bit of a “social experiment” or “trial run,” but added that the odds of success were good.
“New York’s chances of getting a good result, even though it is a densely populated metropolitan area, are actually better than in many rural areas, where they’re not nearly as serious about trying to control the virus,” he said.
However another safety metric — the number of Covid-19 cases per capita — gives some reason for pause. The Harvard report characterized regions with 25 cases per 100,000 people as “red zones” requiring stay-at-home orders for “all learners.” New York, with 23 cases per 100,000 people statewide, was classified as an “orange zone” by this report, a status that the authors said should prioritize in-person education for elementary school and disabled children, followed by children in middle school. High schools should not be a priority for reopening at that level, according to the report.
The C.D.C. and public health experts generally agree on a range of measures that schools should adopt to protect children, teachers, staff members and their families, including mask wearing, physical distancing and improving ventilation in buildings.
Districts across the state have been told to come up with their own reopening plans, all of which must include those safety measures, and are subject to approval by the state’s health and education departments.
Most experts agree schools should skip activities like chorus, band and sports involving physical contact; have children eat in classrooms instead of a central cafeteria; and take steps to prevent crowding in hallways.
“If the cases are under control — and I’m not defining what that means — then I think that there are precautions we can take that make going back to school worthwhile,” said Linsey Marr, an aerosol scientist at Virginia Tech. “If the cases in the community are low, there’s a smaller chance that someone who is infected will show up in school, and the precautions greatly reduce their risk of transmitting it to other students and teachers.”
Like many other experts, Dr. Marr expressed concerns about the academic and developmental costs of keeping children at home, emphasizing the critical role schools play in their well-being and social and emotional development, in addition to academic learning. Schools also provide access to support services and meals for low-income children and facilitate parents’ return to work.
“It is of utmost importance that we educate our kids, and we should do everything possible to do that in person if community transmission is under control,” Dr. Marr said.
School buildings are legally required to have enough air flowing through to fully replace the air every 20 minutes — or three full air exchanges per hour. About 40 percent of school districts in the country need to update their heating, ventilation and air-conditioning systems, according to a Government Accountability Office report. Many schools rely on natural ventilation, meaning just open windows and a roof duct.
Many New York City school buildings are too old and underfunded to overhaul their ventilation systems, and rely mostly on natural ventilation. Joseph Allen, director of the Healthy Buildings Program at Harvard University. said they could institute other measures, such as opening doors along with windows; adjusting the settings in heating, ventilation and air-conditioning systems to bring in more outdoor air in instead of recirculating the indoor air; upgrading filters in the systems; and placing portable air purifiers in some rooms.
Open windows help as long as enough air is coming through, but the typical school can support only about one full air exchange per hour, Dr. Allen said.
A national committee of scientists and educators last month recommended that younger children and those with special needs return in person to school whenever possible. The report by the National Academies of Science, Engineering and Medicine called for measures like hand washing, physical distancing and minimizing of group activities such as lunch and recess.
Even though a small number of children infected with the virus have developed a potentially life threatening syndrome, called Multisystem Inflammatory Syndrome, most studies suggest the virus poses minimal risks to young children.
Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said elementary schools could probably be operated safely, but he predicted that high schools and colleges would face greater challenges staying open. (Mr. Cuomo’s announcement did not address colleges.)
New York will have to continue monitoring cases closely and “apply the brakes” if transmissions start inching up, he said.
Dr. Blackstock said she had seen the number of patients coming in to the Brooklyn clinics where she practices with Covid-19 symptoms fall drastically since April, reassuring her that the city has mostly contained the virus.
As a Black physician who cares for Covid-19 patients, and as a mother of two young children at a public school in Brooklyn, Dr. Blackstock said she had a unique perspective on the epidemic in New York and on the urgent need for children to go back to classrooms.
She said in a Tweet on Thursday that she would send her children back to school for two or three days a week. The response, accusing her of being “anti-teacher” and “anti-educator,” startled her.
“Maybe I was naïve and I didn’t realize how polarized the discussion around schools had become,” she said.
At the public school where Dr. Blackstock’s children are students, the windows don’t open fully and ventilation is poor, but on balance, she said, the benefits of reopening schools outweigh the risks.
“We have to start somewhere,” she said. “I feel we have to at least try.”
Eliza Shapiro contributed reporting.