There are Covid-19 bubbles – small groups of friends or family members who agree to only interact with one another during the pandemic – and then there are the types of bubbles the Flaming Lips have used in recent concerts.

Band members and concert goers rocked and bounced while trapped in large, individual plastic bubbles amid bright, swirling lights in trippy scenes at concerts on Friday and Saturday in Oklahoma City.

The band took elaborate precautions during their live performances to protect themselves from the transmission of the coronavirus, but some health experts were unsure of the effectiveness of these measures.

“I would need to see how the air exchange works between the outside and the inside of the bubbles to be able to tell if it is overall safe or if it reduces the risk of transmission,” said Dr. Eric Cioe-Peña, director of global health at Northwell Health in New Hyde Park, NY

The Friday and Saturday concerts were originally scheduled for December, but the band postponed them due to the increasing cases of Covid-19 in the Oklahoma City metropolitan area.

“It’s a very limited, weird event,” the band’s front man Wayne Coyne told Rolling Stone last month. “But the craziness is that we can enjoy a concert before we endanger our families and everyone.”

“I think it’s a bit of a new normal,” he added. “You might go to a show, maybe not, but I think we can do it.”

In March, Mr Coyne posted a sketch on Instagram showing what the bubble concert might look like.

Nathan Poppe, a videographer and photographer documenting the show for the band, said on Twitter that the floor was constructed in a grid of 10 bubbles by 10 bubbles. “Each bladder can contain one person or two or maybe three,” he said.

Photos showed fans climbing into the balls on the concert floor, where the bubbles were then blown up with leaf blowers.

Each bladder was equipped with a high-frequency speaker, a water bottle, a fan, a towel, and a sign for when someone needed to use the toilet or when it was too hot inside. If it got too stuffy inside, the bladder could be filled with cool air, said Mr. Poppe.

He said concert goers could take off their masks in the bladder but would have to wear them after exiting the bladder.

“You roll your bladder to the exit and open it on the door,” he said.

It was not immediately clear what became of the bubbles used after the 90-minute performances, each attended by around 200 people.

Some health professionals have had concerns about the safety of users in the bladders.

“There is no evidence of the effectiveness – or the absence – of these bubbles from an infectious disease transmission point of view,” said Dr. Sandro Galea, dean of the Boston University School of Public Health.

He said that controlling virus transmission relies on good air circulation and filtration.

“If air filtration is good, protective barriers can theoretically increase and decrease the risk of transmission. However, I would hesitate to go to a concert in a bubble right now unless further researched,” he said.

Dr. Cioe-Peña said the plastic bubbles used at the concerts appeared to be unventilated. But if each of the bubbles had “a bidirectional filtered air supply,” he said, “it would effectively prevent covid transmission between the bubbles.”

While a plastic bladder could help reduce exposure to “infectious agents” when filled with filtered air, it could also lead to increased levels of carbon dioxide in the bladder, said Richard E. Peltier, associate professor of environmental health sciences at the University of Massachusetts Amherst.

“My recommendation would be to add a small CO2 sensor to the bladder,” he said. “While they’re not always the most precise, they should be enough to tell a concert-goer that it’s time to take a break and freshen up the stale air. And then safely enjoy the music again. “

At least 48 new Covid-19 deaths and 2,941 new cases were reported in Oklahoma on Sunday, according to a New York Times database.