• Kids should be able to go trick-or-treating this Halloween with a couple of caveats, Rochelle Walensky, director of the Centers for Disease Control and Prevention, said in an interview with ABC's "This Week" on Sunday.
• Walensky recommended trick-or-treating outside, limiting crowds and avoiding crowded Halloween parties.
• Pfizer CEO and Chairman Albert Bourla said vaccine data for kids ages 5 to 11 would go to the Food and Drug Administration soon. "It's a question of days, not weeks," Bourla said on "This Week."

Kids should be able to go trick-or-treating this Halloween with a couple of caveats, Rochelle Walensky, director of the Centers for Disease Control and Prevention, said on Sunday.

"I certainly hope so," Walensky said on CBS' "Face the Nation" when asked whether it's safe for children to go trick-or-treating this year. "If you're able to be outdoors, absolutely," she said.

The head of the CDC also recommended that parents and kids "limit crowds" on Halloween.

"I wouldn't necessarily go to a crowded Halloween party, but I think that we should be able to let our kids go trick-or-treating in small groups," Walensky said. "I hope that we can do that this year."

On Monday, Pfizer and BioNTech announced a smaller dose of their Covid-19 vaccine is safe and generates a "robust" immune response in a clinical trial of kids ages 5 to 11.

Pfizer CEO and Chairman Albert Bourla said the data would be presented to the Food and Drug Administration soon.

"It's a question of days, not weeks," Bourla said in an interview on ABC's "This Week."

"Then it is up to FDA to be able to review the data, and come to their conclusions, and approve it or not," Bourla said. "If they approve it, we will be ready with our manufacturing to provide this new formulation of the vaccine."

The vaccine for kids age 5 to 11 is "one-third of the dose that we are giving to the rest of the population."

In the meantime, as schools are mostly back in session, the CDC's Walensky told "This Week" that kids who get the coronavirus are, primarily, not getting it while they are at school.

"Our science has actually demonstrated that the disease generally comes in from the community," Walensky said. "When schools are practicing a proper mitigation and prevention strategy, it is not where their transmission is actually happening."

If proper safety precautions are not happening at schools, then transmission is much higher, the CDC chief said.

Most schools, 96%, have stayed open this school year, Walensky said.

"And yet, we also published a study out of Arizona that demonstrated that places that had no masks in place were three and a half times more likely to have outbreaks than places that did have masks in place," Walensky said.

"We know how to keep them safe," Walensky said. "And when we don't use the proper mitigation strategies, they're more likely to have outbreaks and have to close."