ABC News Corona Virus Government. Response

US health officials have a new message: Get the virus in check and you can open schools

CDC director warns low transmission is needed to keep schools open.

"We owe it to our nation's children to take personal responsibility to do everything we can to lower the level of COVID-19, so that we can all get back to school safely," Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, told reporters on Friday.

Redfield pointed to a CDC study released Friday that found child care centers in Rhode Island were able to operate successfully when little virus was circulating in the community. When cases in surrounding areas ticked upward, the virus made its way into the centers, disrupted care and necessitated mandatory quarantines.

"Schools are not islands in and of themselves," Redfield told reporters. "They are connected to the communities that surround them."

It was a subtle shift in messaging for the Trump appointee who just last month was at the White House podium pressing for schools to reopen because, he said, "We really don't have evidence that children are driving the transmission cycle of this."

Since then, the CDC has updated its guidance to note a "body of evidence is growing" that kids "might play a role in transmission." Among those new case studies is an August CDC report on a camp in Georgia where 260 attendees tested positive. That study noted "high attack rates among persons in all age groups, despite efforts by camp officials to implement most recommended strategies to prevent transmission."

That experience has since played out in school reopenings in Georgia and elsewhere, like Mississippi where schools have been forced to close when they realized the virus was too widespread.

The American Academy of Pediatrics updated its guidance on reopening schools this week to take into account new evidence on children over the age of 10 being able to spread the virus as effectively as adults.

"This is on us -- the adults -- to be doing all the things public health experts are recommending to reduce the spread of the virus," said Dr. Sally Goza, the group's president. "If we can reduce the amount of COVID-19 in more communities, it will be possible for more schools to open, and this will be best for all of our children."

Dr. Anthony Fauci, the nation's top infectious disease expert, echoed that message this week by noting that if an area is in a "red zone" -- meaning the percentage of tests that come back positive exceed 10% -- that's makes reopening a school difficult. And letting the virus spread unchecked would result in a devastating death toll because so many American adults have underlying health conditions, including those tied to obesity, he warned.

"When you're in a red zone with ... greater than 10[%] test positivity, you really better think twice before you do that because what might happen is what you've seen: You go in, people get infected, boom, they close it down," he said in a town hall with Healthline this week.

Last month, Dr. Mike Ryan, executive director of the health emergency program at the World Health Organization, warned reopening schools would be a game of "whack-a-mole" until communities took necessary precautions like social distancing and masks.

"We have got to focus on a comprehensive, long-term strategy that focuses on everything at one time. But we can't turn schools into yet another political football in this game," he said.

The CDC study on Rhode Island day care centers released Friday found that strict containment measures helped to stop the spread of the virus. But even with those measures in place, the amount of virus in the community mattered. The more virus in the community, the harder it was to contain.

Those containment measures included wearing masks among adults, limiting class sizes to under 20 people in physically separate spaces and maintaining stable "pods" in which kids and staff members stayed with their group.

In total, COVID-19 cases resulted in the quarantine of 687 children and 166 staff members, including contacts, out of some 19,000 people, according to the report.

Redfield said that case shows "there is a path" and that schools could reopen if their communities take the virus seriously.

Invoking President John F. Kennedy's historic call on Americans to "ask not what your country can do for you, but what you can do for your country," Redfield said wearing a mask, avoiding large gatherings and staying 6 feet apart would go a long way in helping schools to reopen and stay open.

"What we're asking the American public is our ability to bring this outbreak to its knees. It's in our hands. It's in our grasp, but it is going to require all of us to embrace these mitigation steps," he said.

ABC News' Sony Salzman contributed to this report.