“It’s really a no-brainer,” said Andrew Noymer, associate professor [of population health and disease prevention] and epidemiologist at UC Irvine. “Kids are in school. They are interacting with each other every day. Why shouldn’t they go out trick-or-treating? There is no real compelling reason to keep them at home. … I’m sure a lot of the kids don’t want to hear this, and maybe a lot of the parents don’t want to hear this,” Noymer said, before suggesting that everyone — from costumed children to parents to neighbors passing out candy — put on a mask. “I don’t mean a Halloween mask,” he said.