Birx: CDC to issue school reopening advice this week

"What we need to do, and what we’re really trying to do right now is to really look at what the anti-body levels are already in children under 18. So we're launching a very large Sero survey across all age groups to really understand where has this virus been, who has this infected, who is infectable, and who is transmitting the virus."

• Birx said "we know from data today that children do quite well with the virus," but she noted there are "open questions" surrounding whether children under 10 transmit COVID-19 less.
• A study out of South Korea suggests this is the case, she said. "But I think it really needs to be confirmed here," Birx added, saying she hoped the U.S. study would clarify the matter.

Of note: President Trump said Wednesday he would be "comfortable" with his son and grandchildren returning to school in the fall and claimed that "a lot of people are saying" children don't transmit the virus easily.

• But the South Korean study Birx referenced found that children and teenagers aged 10 to 19 can spread COVID-19 at least as effectively as adults do.

• Birx said children with pre-existing conditions "probably should not be in an in school situation where there's active virus circulating."

What's next: Birx told Fox News' Bret Baier school districts needed to plan and be flexible ahead of reopening, with safeguards in place for students and teachers — particularly those with pre-existing conditions who must be accommodated.

• Some schools are putting up plastic shields and many are providing staff and students with masks, she said.

Go deeper:

• Reopening schools is a coronavirus wildcard
• The burden on teachers
• Europe's lessons on reopening schools