Updated Nov. 10 at 11:23 a.m.
Massachusetts school districts that lifted mask mandates immediately after the state relaxed its requirement in February saw far more COVID-19 cases than districts that retained the policy voluntarily, according to a new study published Wednesday in the New England Journal of Medicine.
The new research from authors at Harvard University, Boston University and the Boston Public Health Commission provides evidence for supporters of mask mandates as they call for school districts to enact protections against future surges. But requiring kids to wear masks in schools remains hotly debated, and opponents of mandates say the new study failed to consider the negative impacts that masks can have on children.
The study's authors say their results clearly show masks prevent transmission of COVID-19 in classrooms.
"This just wasn't one week or two weeks after spring break, or a fluke," said Dr. Tori Cowger of the Harvard TH Chan School of Public Health, the journal article's lead author. "There were 15 weeks. And in 12 of those weeks, we saw a significant increase in cases in these school districts. And so it wasn't just a one-time thing. And those cases add up."
The study compared the number of COVID-19 cases in 72 Massachusetts school districts that lifted mask mandates in February to case numbers in Boston and Chelsea, which opted to continue requiring masks through the end of the school year.
Researchers found that, over the course of 15 weeks, those 72 districts saw an additional 45 COVID-19 cases for every 1,000 students and staff — an estimated 11,901 cases overall, or nearly a third of all cases in all districts during that period.
"This evidence indicates that mask policy continued to be an important component of layered mitigation, even in the period in which vaccines are available, and that they can help students and staff stay healthy and in school," said Julia Raifman, an assistant professor at the Boston University School of Public Health, who published an editorial on the subject that ran in the same issue of the New England Journal of Medicine.
"I think this is a time for the federal government to really acknowledge the evidence that mask policies can reduce COVID transmission and do have a role to play in keeping schools safe and in keeping school staff and students healthy and learning in-person in surges," Raifman told GBH News.
Some parents are pushing for mask mandates to have a role in schools going forward. Sarah Horsley has a fourth grader in the Boston Public Schools and is one of the founders of the parents' group BPS Families for COVID Safety.
"This study shows that universal masking protects health and saves days of learning — and also furthers racial equity," Horsley said, noting that the pandemic has disproportionately impacted families of color. "And so we feel strongly that BPS should learn from this study and integrate it into COVID policy going forward."
BPS Families for COVID Safety would like to see mask mandates reinstated in the weeks immediately following Thanksgiving and December breaks, Horsley said, as well as when schools are beginning to experience a surge.
"People can have freedom to wear a mask or not. But when we're in the midst of a surge, people can't have the freedom to impose this high risk of illness on others," Horsley said. "Because kids don't have a choice. They have to go to school, right? And so we need to make sure we're protecting people from illness, from even death in the case of some family members."
Other parents see mask mandates, and the new study, in a very different light.
"What the study does not do is talk about the trade-offs that mask mandates cause for kids," said Melissa Bello, who has two children in the Needham Public Schools and who is a founding member of the parents group Bring Kids Back MA.
Bello said her child has hearing loss and relies on lip reading.
"So it was very, very difficult for him to be in school with people with masks on," she told GBH News.
Public health is about more than just preventing infections, Bello said.
"Public health constitutes mental health, and making sure that people are okay in all facets of life," she said. "And to just have this siloed view on COVID really continues to impact kids and their ability to learn and thrive."
While masks certainly reduce the spread of COVID-19, said Dr. Shira Doron, hospital epidemiologist at Tufts Medical Center, she believes they have a range of negative impacts on kids in schools.
"Masks work," Doron told GBH News. "The reason that that mask mandates were dropped was never because they don't work.
"Most of them chose not to bring masks back because they were there in the buildings, and they were seeing how much better the entire educational experience was for students and teachers," she continued.
The authors of the New England Journal of Medicine article acknowledged that idea in the initial paper, writing that the effects of mask mandates "warrant further rigorous evaluation."
"However, to date, there is no clear existing evidence that masking inhibits learning or harms development," they wrote. "In addition, such effects might be considered alongside the spectrum of benefits of universal masking, including fewer missed school days and staffing shortages, reduced risk of illness for students and their families, and reduced economic hardship for caregivers, who might miss work if their child is sick or if they become ill themselves."
Doron also laid out another critique of mask mandates: contributing to surges of respiratory viruses like RSV. Massachusetts hospitals had to send some children out of state for treatment after the respiratory syncytial virus popped up weeks earlier than usual. Experts pointed out that, in the last two years, kids have had little exposure to the virus under public precautions like masking and social distancing, leaving them vulnerable to infection.
"Continuing to use measures that decrease dramatically the transmission of respiratory viruses may just kick the can down the road and cause further resurgences," Doron said.
Correction: This story was updated to correct the spelling of Sarah Horsley’s name.
