In 1993, after wrapping up her 10th sleepaway summer at Camp Louise, in Maryland, Dr. Megan Wollman-Rosenwald realized that she didn’t want the experience to end. So she found a way to game the system: She went to medical school, then returned in 2016 to her childhood mainstay as an on-site doctor for one week every year.

Dr. Wollman-Rosenwald, now a family medicine physician in Olney, Md., has clocked four more sessions at Camp Louise that way. For the past three summers, she has brought along her daughter, Emmy, who is now 9. But this year, the coronavirus barred both of them from returning.

“It’s really sad,” said Emmy, who misses Camp Louise’s rope course and pasta bar. Worst of all is being separated from her bunkmates, many of whom she sees only once or twice a year.

Emmy and her Camp Louise cohort aren’t alone. Close on the heels of widespread school shutdowns in the spring, sleepaway camps across the nation have begun to cancel their summer sessions to curb the spread of the coronavirus. Last Friday, New York State Health Commissioner Dr. Howard Zucker declared all of the state’s overnight camps shuttered for the season. The state’s day camps have been given a tentative go-ahead and are approved to open on June 29, mirroring similar moves in other parts of the country.

“Throughout this entire public health response, there isn’t a single decision we have not made based on data and science, rather than emotion,” Dr. Zucker announced in a written statement.

The case for cracking down on camps does come with scientific backing. Camp would not be camp without its cadre of youngsters and counselors, a congregation that is not very compatible with the dictums of distancing. In these close-knit environments, it is easy to contract viruses, bacteria or other microbes that brew in airway droplets or linger on dirtied hands. Studies have documented numerous instances of infectious illnesses sending American campers to the infirmary, occasionally in droves, plagued by gastrointestinal disease or respiratory viruses like those that cause measles and mumps.

Camp epidemics can and do happen, and on-site staff aren’t always prepared. A 2017 survey of camps in the United States and Canada found that 15 percent of respondents lacked clear protocols for outbreaks of illness. And only a quarter of the camps had collaborated with medical organizations to put together disaster preparedness plans.

Early data suggests that the coronavirus only infrequently saddles children with serious disease, and may be less likely to infect younger people generally. But “we can’t say children are wholly unaffected,” said C. Brandon Ogbunu, an evolutionary biologist and epidemiologist at Yale University. Recent evidence indicates that some children who are infected with the coronavirus are struck with a rare inflammatory syndrome that produces serious symptoms.

Sleepaway camps can be especially tough to manage. Campers typically spend their days mingling in close groups, often without reliable access to soaps and disinfectants, before hunkering down in tightly quartered bunks for the night. These practices inevitably increase the number of personal interactions among children, potentially heightening the risk of disease transmission, compared to a day camp that runs for only a few hours a day, Dr. Ogbunu said.

“There’s no way to socially distance with an overnight camp,” Dr. Wollman-Rosenwald said.

But day camps aren’t necessarily better. Children who catch the virus in these settings could take it home to their family. Asymptomatic transmission is known to play a substantial role in the pandemic, and daily camp commuters could unknowingly provide opportunities for microbes to travel.

With modifications, overnight camps could actually be some of the safest options for summer, said Dr. Pardis Sabeti, a computational biologist at Harvard University and the Broad Institute. Adequate testing would be a must for all — campers, counselors and staff members — before arrival; and everyone would probably need to remain on-site full time, effectively walling themselves off from society for the camp’s duration. Each cabin of campers could then become its own family unit, interacting with only one another and minimizing contact with other “households” — mirroring what is already happening in many American neighborhoods.

It would make for an unconventional camp, but perhaps better than nothing, Dr. Sabeti said, adding: “Kids want contact. I don’t believe we’re going to have our children stay six feet away from each other in perpetuity. So why not do something different?”

Many camps may not be prepared to pivot in this manner, or to include extensive distancing. And parents like Sarah Peterson, in Atlanta, with her husband and two daughters, worried that some measures could strip the sleepaway camp experience of its charm. “Camp is really about intimacy and forming your own independent relationships,” she said. Before the pandemic, Dr. Peterson’s 9-year-old daughter, Fiona, had been looking forward to her second stint at an overnight camp in Maine, which has since been canceled.

Overnight camps would have also offered a reprieve for exhausted parents like Dr. Peterson — especially after months of full-time schooling at home. Now, without teachers and homework to keep young minds occupied, “it feels like we’re doubling down,” she said.

In New York and elsewhere, day camps have started to cancel their summer plans as well. Others have transformed too much for some parents. Amanda Monschein, who works as a daily money manager in Maryland, was originally planning to send her 8-year-old daughter, Sofie, to camp this summer.

But the camp’s directors have imposed protocols to stymie the spread of disease, including a face mask mandate and a reduced camper-to-counselor ratio. Although the changes are in line with C.D.C. guidelines, they have nearly doubled the camp’s price tag. Campers also won’t be allowed access to the camp’s pond, where they would normally go to cool off in the Mid-Atlantic heat.

Dr. Peterson’s daughters are still signed up for a nature camp called Kids Go Wild, scheduled to begin in July. In an email to parents, the camp’s directors said that they would start administering daily health screening questionnaires and temperature checks, and impose sparser seating at activity tables, each equipped with its own handwashing station. “Part of the way they run this camp makes it feel safe,” Dr. Peterson said. “I think really tiny groups that hang out outside, especially summer, is a great way to do it.”

In Maryland, 9-year-old Emmy Rosenwald reminded her mother that things won’t really return to “normal.” But she’s hoping to enjoy a full decade of Camp Louise, just as Dr. Wollman-Rosenwald did. Pending improved containment — and good hygiene — Emmy said she thinks “we should still be able to go to camp next year.”

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