The U.S. Department of Education has launched a civil rights investigation into five states that have barred indoor making mandates, alleging that the governors are creating an unsafe learning environment for students with disabilities at heightened risk of severe illness from COVID-19.

It’s an aggressive new legal tact from the Biden administration to challenge Republican governors who insist indoor mask mandates don’t work.

The Centers for Disease Control and Prevention has found that schools are generally safe if students and staff universally wear masks. School districts that struggled with COVID-19 outbreaks this year – often sending thousands of kids home – typically did not require masks.

The investigation's focus is on Iowa, Oklahoma, South Carolina, Tennessee, and Utah. The Education Department says it is not including Florida, Texas, Arkansas and Arizona at this time "because those states’ bans on universal indoor masking are not currently being enforced as a result of court orders or other state actions," federal documents state.

Read more here.

-ABC News’ Libby Cathey and Anne Flaherty

The benefits of getting a COVID-19 vaccine outweigh the risk of getting myocarditis from the vaccine, CDC experts say, adding that it's even more apparent now that cases are spiking among young people.

The risk of getting myocarditis - inflammation from the heart muscle – from the virus is much higher than getting it from a vaccine, scientists said at a CDC advisory panel Monday, pointing to new data.

The CDC estimates that the risk of myocarditis for the highest risk group -- young males age 16 to 17 -- is about 73 cases per million doses of the Pfizer vaccine.

The public health agency also estimates that 56,700 cases of COVID-19 would be prevented in that same age group for every million vaccines.

In addition, the risk of myocarditis after actually getting COVID-19 is six to 34 times higher than it is from getting a vaccine.

-ABC News’ Cheyenne Haslett

As of Aug. 29, dozens of states were reporting limited beds in intensive care units, with 23 states reporting over 80% capacity and six states reporting over 90% capacity, CDC experts announced at an advisory panel Monday.

The panel also found that the risks of contracting COVID-19 are still much higher for the unvaccinated.

People between ages 18 and 49 are 24 times more likely to be hospitalized if unvaccinated, according to the CDC, 19 times higher for unvaccinated populations between 50 and 64 and 13 times for unvaccinated people 65 and older.

-ABC News’ Cheyenne Haslett

The COVID-19 vaccines' ability to keep people out of the hospital appears to be dropping slightly, particularly for those 75 and older, although the vaccines still remain highly effective at preventing serious illness, according to an analysis by the Centers for Disease Control and Prevention presented Monday during an advisory panel.

The CDC has previously estimated that 97% of people in the hospital being treated for COVID-19 are unvaccinated, but that data was collected before the spread of delta, a hyper-transmissible variant that many doctors have warned appears to be making people sicker.

Health experts are also concerned that a person’s immunity could be waning over time, particularly among older people whose bodies are less likely than young people to develop a strong immune response to the vaccines.

The latest CDC analysis estimates that the ability of the COVID vaccines to keep a person out of the hospital is now between 75% to 95%.

For people older than 75 in particular, vaccine effectiveness against hospitalization experienced the steepest decline, from more than 90% to 80% between June and July.

However, the vaccines still remain highly effective at preventing serious illness, according to the briefing. "COVID-19 vaccines continue to maintain high protection against severe disease, hospitalization, and death," the CDC notes.

-ABC News’ Anne Flaherty

Nearly 350 children are currently hospitalized with COVID-19 in Texas, state data shows.

According to the Texas Department of State Health Services' online COVID-19 dashboard, which was last updated on Sunday afternoon, there are 345 pediatric patients in hospitals across the Lone Star State. That number was up from 282 on Thursday afternoon.

The data also shows there are 73 staffed pediatric intensive care unit beds available in all of Texas.

Since the new school year began in Texas last month, some 52,000 students have tested positive for COVID-19, according to the data.

-ABC News' Gina Sunseri