Despite suffering from bronchitis at the beginning of the semester, Valeria Pappas-Brown, 48, soldiered on to teach biology classes at the Community College of Baltimore County. The part-time instructor suspects that trudging from one class to another — instead of resting — prolonged her illness. But she could not afford to miss class.

“Because of the pay, because of the sick leave — I just don’t have enough accrued — I can’t take any time off,” Pappas-Brown said.

She fears the possibility of once again having to choose between her health and her financial well-being as Maryland and the rest of the nation contend with the novel coronavirus pandemic.

The spread of the coronavirus in the United States is rattling adjunct instructors. Few receive health insurance through the colleges and universities where they work, and fewer still have paid sick leave. Even adjuncts with access to paid time off say there are barriers that impede their ability to take advantage of the benefit.

The Families First Coronavirus Response Act held out hope that any workers sidelined by the disease could count on paid time off. But in a compromise to pass the legislation, lawmakers narrowed the leave provision to apply to only employers with 500 or fewer workers. That effectively carves out many private colleges and universities — most have more than 500 employees — and leaves part-time instructors out in the cold.

As colleges try to mitigate the impact of covid-19, adjuncts are imploring schools to consider instructors’ vulnerability.

In New Jersey, the adjunct faculty union at Rutgers University wrote the school’s president, Robert L. Barchi, last week requesting he extend health care to part-time lecturers or at least provide free access to campus clinics. Instructors say without this access, adjuncts who lack health insurance are unlikely to get tested for the coronavirus, even if symptomatic.

Rutgers officials said in response to questions from The Washington Post that there will be no changes to the existing health-care plan, offering no further explanation.

“Not only would denying us access to basic health-care services amount to a grave failure of leadership, it would also be the clearest expression from the Rutgers administration that our lives are truly unimportant to them,” said Bryan Sacks, treasurer of the union for part-time faculty workers at Rutgers. It is part of the larger American Association of University Professors and American Federation of Teachers.

Part-time adjunct instructors represent two-fifths of all faculty at the nation’s colleges and universities. Some hold full-time jobs in their field and teach a course on the side. But for others, their primary source of income comes from cobbling together multiple classes, sometimes at multiple colleges. And that model can complicate their access to even state-mandated time off.

“Many adjuncts may be teaching four or five classes at a time, but not more than one or two at any specific university, so they don’t necessarily hit the threshold for earned sick leave,” said Rebecca Kolins Givan, an associate professor of labor studies at Rutgers. As a result, “their employer may not be obligated to provide any of the benefits that other workers receive.”

Maryland is one of a dozen states and the District that require companies to provide all workers paid sick leave. Employers must grant one hour of leave for every 30 hours worked in Maryland. But accruing time off can be a Sisyphean task for adjuncts who are in class just a few hours a week.

“I accumulate like an hour a month,” Pappas-Brown said. The time she spends preparing for class, grading papers or meeting with students does not factor into her work hours, which is the case for most adjuncts.

After losing her job as a medical researcher two years ago, Pappas-Brown struggled to find full-time employment and wound up teaching for a fraction of her old salary. There are no health-care benefits for part-time instructors at the community college, so the trained infectious disease researcher is on Medicaid.

The roughly $7,100 she will earn this semester teaching three courses is barely enough to cover her bills, let alone her daughter’s college tuition. Pappas-Brown has dipped into her 401(k) retirement fund more times than she cares to count. There is no financial cushion, no contingency plan if she falls ill.

“I’d just have to work through it,” Pappas-Brown said. “Sometimes, there is just no plan.”

Hope H. Davis, a spokeswoman for the Community College of Baltimore County, said the school will allow adjunct faculty to “borrow” against future sick leave if they fall ill or need to be quarantined because of the coronavirus.

As policies addressing the disruption caused by the coronavirus evolve daily, some colleges and universities are granting all faculty more liberal leave. On Friday, the University System of Maryland, which oversees 12 state schools, said adjuncts and graduate assistants who are unable to work as classes transition online can receive an excused absence without loss of pay.

“Our goal is to urge all of the institutions to be as flexible as they can possibly be,” said Carolyn Skolnik, associate vice chancellor for finance and administration at the University System of Maryland. “We didn’t want to see employees feel like they would end up in a bad economic situation if they didn’t come to work.”

Adjuncts at some universities say that while they are sympathetic to the pressure administrators are under, they are disappointed in the lack of communication with part-time faculty in the midst of this health crisis.

At La Salle University in Philadelphia, theology instructor Daniel Reginald S. Kim said the Roman Catholic school has discussed only the benefits afforded to full-time faculty during the outbreak. La Salle provides part-time employees who work a minimum of 15 hours a week some paid sick leave, but adjuncts are often shut out of the benefit because they don’t meet the threshold.

“You’re seeing all of these resources that are available to the full-time people, whether it’s faculty and staff, and you’re reflecting on your own position. You’re saying to yourself, they have all of this and I don’t,” Kim said. “This is a moment that is really amplifying that full-time versus part-time status.”

La Salle University spokesman Christopher A. Vito said the school is “taking measures amid these extraordinary circumstances to remain as nimble as possible and ensure we are caring for our community.” The university, he said, will review all cases on an individual basis.

Teresa Greene, 73, who has taught psychology since 2006 at Valencia College in Orlando, said there has been no discussion about the parameters of the leave policy for part-time instructors at her school.

“The one message we got from the provost of the college was all about how we can accommodate our students … which is rightly our concern, but not one word about faculty,” Greene said. “Not one word about what will happen if they have to miss class.”

Adjuncts earn a half-hour of emergency leave for every hour in the classroom at Valencia, but only once a term. Someone who teaches a three-hour course, for instance, would be entitled to 1.5 hours of paid leave for the entire semester. The time off is not cumulative and does not roll over to the following term, said Greene, who would like some flexibility in the policy.

Valencia spokeswoman Carol Traynor said: “Should a part-time faculty member become ill and need to self-isolate, we would work directly with that faculty member and the dean to determine how best to support the individual through the illness or isolation period.”

On Thursday, the college announced a temporary paid leave benefit for full- and part-time employees in light of the coronavirus.

Valencia is one of seven state colleges in Florida where adjunct instructors in the past year filed to join the Service Employees International Union to improve working conditions.

Part-time faculty throughout higher education have made headway in securing paid leave and health insurance through collective bargaining, although experts say they still have a long road ahead. Sick leave provisions have become more common in adjunct contracts at public colleges than private universities, according to the National Center for the Study of Collective Bargaining in Higher Education and the Professions at Hunter College.

“Some schools have been forced to provide more security for their adjuncts because of the pushback from students and other faculty,” said Mark Gaston Pearce, executive director of the Workers Right Institute at Georgetown University Law. “You’re going to see more of that.”

Pearce, a former chairman of the National Labor Relations Board, compared the plight of adjuncts to graduate student workers who also fight for fair compensation and benefits. Contingent faculty — a classification that includes part-time adjuncts, full-time instructors who aren’t on a tenure track and graduate student workers — account for nearly three-quarters of instructional staff in higher education but are largely invisible and economically vulnerable in times of crisis.

“What the virus is showing … are the holes in the safety net and the social fabric of our country,” Randi Weingarten, president of American Federation of Teachers, said. “Adjuncts are basically highly educated people who are just making it paycheck to paycheck.”