The science behind the state’s school mask policy is outdated, some experts say. Should the benchmarks change?

Some doctors question whether a mask mandate is still necessary in all schools.John Tlumacki/Globe Staff/file

With the Omicron surge receding and the number of COVID-19 cases among Massachusetts students starting to decline, debate is growing about whether the state’s mandatory school mask rules should be revised or removed.

Massachusetts’ current policy, developed as the Delta variant emerged last summer, allows local officials to lift the mask requirement if they can demonstrate that at least 80 percent of all students and staff in a school building are vaccinated.

On Jan. 10, state Education Commissioner Jeffrey Riley extended the policy through Feb. 28. He also allowed, for the first time, nonvaccinated people in schools that achieve the 80 percent threshold to also go maskless.

“Policies that were developed for the fall semester need to be updated to reflect where things stand now, not where they stood in the fall,” said Dr. Westyn Branch-Elliman, an infectious diseases specialist and an associate professor of medicine at Harvard Medical School, who advises state education leaders on COVID and helped develop the mask policy.

Moreover, some experts noted that the flood of breakthrough infections during the Omicron surge indicates that vaccination rates alone are not a good enough benchmark for deciding when to mask or unmask.

Another adviser to the state, Dr. Elissa Perkins, director of emergency medicine infectious disease management at Boston Medical Center, said the current mask requirement is now obsolete because it is based on vaccination rates. And while the shots proved effective at preventing severe disease and death, they fell short in preventing transmission.

“We are going to have to learn to live with the virus,” Branch-Elliman said. “And that means making some hard decisions about what mitigation measures we want to maintain in the long term.”

The state Education Department declined to say whether its rationale for the mask rule is outdated. But the agency did note that the high rate of vaccination among eligible children and updated school testing strategies are helping stem transmission in schools.

“The department continues to consult with doctors about the current mask requirement, and all other mitigation strategies, and will update its guidance before Feb. 28,” spokesperson Colleen Quinn said in a statement.

Quinn declined to say what parameters the department is considering.

But Branch-Elliman and Perkins are advocating for making masks optional now. In a recent Washington Post op-ed, they said that with N95s and other high quality masks becoming more available, schools should be allowed to switch to a policy of “personal choice regarding self-protection and supporting those who choose to remain masked,” rather than continuing mandates. N95s, they said, are “highly effective at protecting their wearers, regardless of what people around them are doing.”

The article, which drew heated debate on social media, also linked mask-wearing to learning and social development problems in children, arguments that scientists have yet to sort out.

Numerous other infectious disease and public health specialists said it’s too soon for schools to remove masks in Massachusetts because infection rates remain too high. State data show that while cases among school-age children have declined in the past two weeks, they are still more than twice the levels before Omicron hit in late November.

But experts did suggest the state use a range of benchmarks as it considers updating its mask rule. Those include linking mask requirements to the amount of COVID detected in waste water, or to the infection rates in local communities, or the ability of hospitals to handle increased caseloads.

“Nevada has a simple and clear mask policy,” said Dr. Jonathan Levy, who chairs the department of environmental health at Boston University’s School of Public Health.

Nevada requires masks indoors when infection rates are substantial or high in a county, following Centers for Disease Control and Prevention thresholds. And when the rates go below that level for two consecutive weeks, the masks aren’t required.

“You could certainly envision a policy like that for schools,” Levy said. “Policies that are clear and straightforward and logical are more likely to be accepted.”

Or as as Robert Hecht, an epidemiology professor at Yale University’s School of Public Health, put it: “Balance technical perfection and wonkiness with the ability to get communities to buy in.”

Shan Soe-Lin, managing director at Pharos Global Health Advisors, a Boston health advisory firm, said the state should consider a system that requires school masking when the level of COVID starts rising in waste water. That tracking has proved effective as an early warning sign for COVID’s peaks and valleys.

“It’s much better than test positivity rates because people may get tired of testing, or they’re relying on at-home tests,” where results are not reported to officials, Soe-Lin said, “so there’s a lot of wobble in test positivity rates.”

The American Academy of Pediatrics and its Massachusetts chapter continue to urge masks in school. Dr. Lloyd Fisher, a Worcester pediatrician and president of the state chapter, envisions a mask model that considers whether hospitals are swamped with patients.

The issue is complicated by recent changes from the CDC, shortening isolation time for people with COVID from 10 days to 5, followed by 5 days of mask wearing in public, guidelines Massachusetts adopted.

Scientists believe people can still transmit the virus for several days after the five in isolation. That’s prompted concerns about potential transmission when students just back from isolation remove masks to eat, and whether that transmission may inadvertently spread infections to other families who have members with a weakened immune system.

Now, many are closely watching Cohasset, one of a handful of communities that has moved to lift school masking. The South Shore town allowed vaccinated high school students and staff in December to go maskless, and then extended that policy to its middle school on Jan. 18.

The next day, its school committee voted to allow unvaccinated students and staff in those buildings to remove masks, too, though the town’s Board of Health “strongly” recommended masks continue for everyone at least through the end of January.

Craig MacLellan, the school committee’s chairman, said many students have opted to continue wearing masks. COVID infections were higher in the high school after the December holidays compared to those in the middle and elementary schools — roughly 9 percent, versus around 7 percent and 5 percent in the middle and elementary schools, he said.

“Since then, infections have gone down,” MacLellan said. But “there’s a ton of anxiety that people harbor around this.”

He has received lots of calls seeking insights and tips from families and school committee members outside Cohasset, where 95 percent of eligible residents are fully vaccinated.

“This is a challenging circumstance and I don’t know whether there is a right answer for one community to the next,” he said. “It may not be compatible with the unique needs of other communities. We don’t purport to have the answer.”