CDC Director Tom Frieden said on ABC’s “This Week” that while the agency is looking closely at suggestions “try as we might, until the outbreak is controlled in Africa, we can’t get the risk here to zero.”

“We’ll absolutely look at any suggestion that is workable and that wouldn’t backfire,” he said.

“We don’t want to do something that inadvertently increases our risk by making it harder to stop the outbreak there.”

Frieden said he remains “quite confident we will not have a widespread outbreak” in the United States.