Cases of COVID-19 have climbed steadily in Baltimore-area public schools in recent weeks, but education leaders say they have limited plans to reinstate masking mandates.

Maryland Department of Health data show this week that cases of transmission in schools have risen across the region since students and educators returned from spring break around April 19.

The data, however, doesn’t account for every case. Schools tally transmissions that occur on campus, but not every case among students, who may have contracted the virus at home or elsewhere.

Maryland schools similarly faced an uptick of cases following the winter holidays in December, prompting some jurisdictions to extend their breaks to allow time to test students for the virus.

Public policy around masking in schools has shifted dramatically since then. The Maryland State Board of Education voted to end the statewide masking requirement in schools on March 1, with Baltimore City and Baltimore, Anne Arundel, Carroll, Harford and Howard counties systems following suit later that month.

Public health experts have been recommending indoor masking, in addition to vaccinations, to prevent COVID-19 infections with each wave of infections.

Dr. Eric Toner, an emergency physician and a senior scientist in the Johns Hopkins Bloomberg School of Public Health, said the spikes in some schools show how the virus easily spreads and “indicates that we all should be wearing good quality masks when in crowded indoor spaces.”

But there have been few calls for mandates from public officials.

Dr. Letitia Dzirasa, the Baltimore health commissioner, issued a public warning Tuesday urging people to wear masks indoors following a 243% jump in cases citywide in the past month. However, she said she wouldn’t call yet for a new mandate because risk remains low according to guidance from the U.S. Centers for Disease Control and Prevention, which is closely watching COOVID-related hospitalizations.

Baltimore City schools CEO Sonja Santelises acknowledged the rise in cases Tuesday during a school board commissioners meeting. The system, which serves about 77,000 students, recorded 123 positive cases this week, according to state data.

Santelises told commissioners this week that schools will enforce masking for all close contacts and any classroom with three or more linked cases.

At least one city elementary school imposed a schoolwide mask mandate for the next 10 days, according to an email sent home to parents. City schools spokesman André Riley said that masks are required in “certain circumstances like an outbreak.”

Baltimore City schools implemented a test-to-stay policy and never halted its asymptomatic testing of some students, Santelises said.

“We are much better prepared than we have ever been,” Santelises said. “Our health and safety coordinators are ready and the COVID response team is monitoring positivity levels and close contacts.”

City schools also sent students home for spring break with rapid test kits as a “proactive measure,” officials said at the time. The system also is offering additional testing in preparation for overnight or out-of-state field trips, according to Santelises.

Larry Simmons, chair of Baltimore’s Parent and Community Advisory Board, suspects schools are hoping they won’t have to reinstate a universal masking mandate, but the uptick in cases may cause some to reconsider.

“I appreciate that they’ve mandated in schools with higher [transmission] numbers,” Simmons said. “But I hope they make parents aware [of cases] so they are comfortable making choices that are best for families and children.”

Simmons said parents who feel the urge to mask their children should follow their instincts to do so.

In the neighboring Baltimore County school system, which serves approximately 111,000 students, cases have risen steadily over the past few weeks. The system has counted 279 cases, according to state data.

“Like everyone else and everywhere else, we are seeing an increase in cases,” said county schools spokesman Charles Herndon. “We have not made any significant changes to our protocols, but we continue to report all cases, including clusters of cases that might be considered outbreaks according to the state, and communicate when cases occur in schools to make sure that parents remain informed and aware.”

Baltimore County schools, which saw fierce resistance from some parents to masking mandates, were among the first in the region to rescind the mask mandate after the state board of education returned the decision to local jurisdictions.

With the surge in cases, there might be a time when schools should reconsider mandates, said Dr. William Moss, and infectious disease expert and executive director of the Johns Hopkins University International Vaccine Access Center.

“Masking is a tough one,” he said. “There’s so much push back. Schools will need to make individual decisions based on the number of cases in school or in the community and should have some kind of trigger as to when they have universal masks.”

However, he said, knowing when such a threshold is crossed is also tough because of the lack of accurate data on cases.

Other local educational institutions are facing similar dilemmas. More than 1,300 people signed a petition calling for Johns Hopkins University’s undergraduate final exams to be held online given the rise in cases. The university also reinstated its masking mandate following a rise in cases after spring break, as did the Community College of Baltimore County.

And Howard County schools, which serve about 57,000 students, has counted at least 300 cases. At one school, Worthington Elementary School, 27 people tested positive as of Monday. Spokesman Brian Bassett said the school system is continuing to follow the protocols that have been in place throughout the pandemic.

Anne Arundel County schools counted 313 cases. A spokesman did not respond to a request for comment about the rise in cases this week.

Meanwhile, Carroll and Harford county public school systems counted 22 and 51 cases, respectively.

Baltimore Sun editor Steve Earley contributed to this article.