Pre-pandemic, ball pits were a thing. Filled with colorful plastic balls and teeming with kids, they were a staple of fast-food play areas, birthday parties and fun centers.

Then came COVID-19, and ball pits suddenly seemed a spectacularly bad idea. They largely shut down. Now, as we slowly emerge, restaurants and fun centers presumably are weighing their options.

Could ball pits make a comeback? Or, perhaps more to the point: Should they?

Ball pits raised eyebrows even before the pandemic, given the participating children who might mouth balls, sport runny noses and not thoroughly wash their hands after using the bathroom.

"We always kind of joked they were a hotbed for disease before the pandemic," said Jill Roberts, microbiologist with the University of South Florida College of Public Heath. "The reality is anyplace you have a lot of kids, you're going to have that kind of problem."

One potential problem, at least short term: "Unfortunately, the young kids that are going to be playing in these ball pits are not going to be vaccinated," said Dr. Meghan Martin, pediatric emergency room doctor at Johns Hopkins All Children's Hospital in St. Petersburg, Fla.

The vaccine recently became available to those 12 and older, but younger (presumably ball pit-aged) kids can't get it yet. Dr. Anthony Fauci, chief medical adviser to the president, recently said that the younger set will likely be able to get vaccinated by the end of the year or the first quarter of next year.

Dr. Cindy Prins, associate professor of epidemiology in the College of Public Health and Health Professions at the University of Florida, said the ball pit "is not inherently an evil place."

"To me it's not the ball pit, it's the distancing," she said. "It's all about taking the regular precautions ... just trying to minimize that airborne and droplet spread."

Parents are urged to keep up that regimen of hand-washing and other infection prevention measures.

"We have wonderfully short memories," Prins said. "We go back to our habits very quickly."

In the end, adults will have to assess the risks vs. benefits of ball pit participation.