As it considered whether to lift its masking requirement Monday night, the Wallingford-Swarthmore School District considered an array of questions: What level of coronavirus transmission would justify doing so? How much time should families have to get their children vaccinated? What if parents want their children to remain masked, but students don’t wear them?

One school board member proposed that ending masking be tied to vaccination rates — a scenario the district’s lead COVID-19 nurse said was complicated because of the difficulty estimating herd immunity.

In the end, the Delaware County district proposed going mask-optional as of Feb. 7 if case counts over the previous two weeks amount to less than 2% of students and staff — a threshold that could vary by school building.

“I think we would all agree that our No. 1 goal is to keep kids in school full time, keep our activities running, and keep the school experience as much as it can be similar to pre-pandemic life,” David Grande, the board’s vice president, said during the meeting Monday.

With Pennsylvania’s school mask mandate struck down by the state Supreme Court last week, districts across the region are confronting the question of what to do about masks, and the choice isn’t as simple as whether to wear or not to wear. Schools are making very different decisions.

Some districts — including many in Bucks County — immediately allowed students to go maskless. Others are still requiring masking, including Philadelphia, where the health department noted its indoor mask mandate remains in effect and called masking “crucial” amid a surge in COVID-19 cases.

In Montgomery County, officials said they were encouraging districts to continue masking, noting CDC recommendations. At least one district in the county — Cheltenham — said it plans to require masks for the rest of the school year.

In announcing continued masking requirements, several districts said they would soon be revisiting the issue: Radnor told parents that “several masking options” would be discussed at the next school board meeting Dec. 21, while West Chester said it would take up its masking plan in January, giving older students time to get a booster and the district “the opportunity to assess the impact of 5-11-year-old students who are fully vaccinated.”

The contrasting approaches have played out through much of the pandemic, driven in part by guidance from county health officials but also community preferences and partisan divisions. Before the state imposed the mask mandate this fall, district requirements varied. And once the mandate took effect, some districts made it easier than others to receive exemptions, granting significant numbers of students permission to go unmasked.

But the Pennsylvania Supreme Court’s order late Friday pushing the decision back to the local level sparked a new wave of frustration among parents unhappy with how their districts are managing the pandemic.

For parents like Kate Radvansky, an internal medicine physician whose daughter attends first grade in the Council Rock School District, immediately ending the requirement made no sense.

“Cases are up, and it’s two weeks out from the holidays — why are we trying to do this now?” asked Radvansky, who kept her daughter home from school Monday after her district made masking optional along with others in Bucks County, including Central Bucks, Pennridge, Quakertown, Bensalem, and Neshaminy.

Radvansky — who called her daughter’s teacher and learned she didn’t plan to mask — said she doesn’t want masking indefinitely, but “I fail to understand why it’s such a big deal to continue what we’ve been doing for a year.” She noted the American Academy of Pediatrics’ support of school masking; the group’s Pennsylvania chapter said earlier this month it was “troubled” by Gov. Tom Wolf’s plan, announced beforethe court decision, to end the school mandate on Jan. 17.

“I just feel like we’ve been hung out to dry,” Radvansky said. Council Rock Superintendent Robert Fraser didn’t return requests for comment Tuesday. In an email to parents Sunday, Fraser said: “All students and all staff should feel equally comfortable with their choice to wear a mask or to not wear a mask.”

Districts in Bucks weren’t alone in lifting mask requirements. The Ridley School District moved from requiring to “recommending” masks Monday at the direction of the school board, which had heard “very strong” calls from families that they wanted a choice on masking, said Superintendent Lee Ann Wentzel. She was “pleasantly surprised” that most students at the high school appeared to still be wearing masks Tuesday.

Requiring masks “can be an option, should we see a need with numbers going up,” Wentzel said. Elsewhere in Delaware County, Marple Newtown made masking optional, and Springfield did so for seventh to 12th grades — saying it would follow suit for younger students on Jan. 17, giving those children a “reasonable amount of time to be fully vaccinated.”

Districts that immediately lift mask requirements “may see a bump in transmission if their community has lower vaccination rates, especially among school-aged children and teens,” the CHOP PolicyLab research group wrote in a blog post last week.

David Rubin, PolicyLab’s executive director, said Tuesday that he would not advise stopping masking “until at least after the holidays,” once cases are declining — an approach he predicted most area suburban districts would take. For a district as big as Philadelphia, he said, the question would be complicated by crowded classrooms and the challenge of scaling testing programs across 200 buildings, among other factors.

But he said it makes sense for schools to be considering the future of masking: “We understand the fatigue that people have,” and “the milestone we’ve reached” with vaccinations available to everyone 5 and older, Rubin said. In its post, PolicyLab noted that “children have been asked to shoulder a tremendous burden” during the pandemic, and “concerns about mental health and the impacts of prolonged periods of restrictions are increasingly important.”

It would help schools get back to normal if vaccination rates were higher, Rubin said. Through its program providing COVID-19 testing to schools, CHOP has found only about 20% of children ages 5-11 in the region may be vaccinated.

Though the positivity rate among students in the testing program declined last week — just 1.2% of students who were close contacts of someone with COVID-19 tested positive, down from 2.7% the week before — Rubin said the relatively low vaccination rate among younger children was “not going to slow the regional rise at this point.”

In Wallingford-Swarthmore, where the board considered but didn’t vote on the new plan Monday — having previously given school administrators the power to make the changes on their own — several board members said they had been uncomfortable with the prospect of removing masks but felt the approach was reasonable. One called it a “leap of faith,” but shaped by expert opinion; administrators said they were regularly in touch with the PolicyLab.

They also noted that a surge in cases would trigger a return to masks. The 2% threshold proposed by the district is higher than the district’s current case incidence rate, which was 0.47% for the two weeks after Thanksgiving.

School leaders said they anticipated optional masking would increase the need for capacity in the district’s “test-to-stay” program, which allows students who are close contacts of a person with COVID-19 to remain in school if they test negative for the virus. Currently, students who are masked are exempt from quarantine requirements.

The Pennsylvania Supreme Court has not yet issued an opinion accompanying its Friday order, which affirmed a Commonwealth Court ruling that acting Health Secretary Alison Beam had overstepped her authority in issuing the mandate. Beam on Monday announced she would resign at the end of the month.