(CNN)The United States is facing a pivotal moment in the coronavirus pandemic, given that the Delta variant is spurring surges in cases and hospitalizations: It must increase vaccinations or risk magnifying the impact, the surgeon general said.
"If we want to keep our kids in school, if we want to protect the economy, if we want our country to get through this pandemic, we have to leave no stone unturned in making sure people get vaccinated," US Surgeon General Dr. Vivek Murthy told CNN's Anderson Cooper on Thursday.
Murthy's comment came after President Joe Biden announced that federal employees must attest to being vaccinated against Covid-19 or face strict protocols, including testing once or twice a week, wearing a mask and other heath mitigation measures.
On Friday, the Centers for Disease Control and Prevention shared a new study that led to its new indoor mask guidance, showing the Delta variant produced similar amounts of virus in both vaccinated and unvaccinated individuals if they get infected.
"High viral loads suggest an increased risk of transmission and raised concern that, unlike with other variants, vaccinated people infected with Delta can transmit the virus," said CDC director Dr. Rochelle Walensky said in a statement Friday.
The finding "was a pivotal discovery leading to CDC's updated mask recommendation," Walensky said.
Walensky defended the agency's guidance on wearing masks in schools Friday evening, telling Fox News it was necessary to protect kids, their families and communities.
"Right now the best way to (prevent outbreaks in schools) is to have everybody masked because we do have disease in the community," she said. "And hopefully as we have vaccinations for kids, and less disease in the community, we'll be able to scale back on the mask wearing."
Also emerging late this week: The Delta variant appears to cause more severe illness and spread as easily as chickenpox, according to an internal document from the CDC.
The document -- a slide presentation first reported by The Washington Post -- outlines unpublished data that shows fully vaccinated people, even if they don't get sick, might spread the Delta variant at the same rate as unvaccinated people.
Meanwhile, coronavirus case rates have jumped as the Delta variant has increased its grip in the United States.
The US averaged more than 66,900 new daily cases over the last week -- an average that's generally risen since the country hit a 2021 low of 11,299 daily cases on June 22, according to Johns Hopkins University data.
Hospitalizations have also risen. More than 39,000 Covid-19 patients were in US hospitals on Monday -- a number that's generally risen since a 2021 low of nearly 15,988 on June 27, according to Department of Health and Human Services data.
Data shows a difference between areas with high and low vaccination rates.
Average hospitalization rates are nearly three times higher in states that have fully vaccinated less than half of their residents compared with those that have vaccinated more than half of their residents, according to a CNN analysis of federal data.
And Covid-19 case and death rates over the past week are more than twice as high among states that have vaccinated less than half of their residents, on average.
With only 49.5% of Americans fully vaccinated, former US Surgeon General Dr. Jerome Adams said Thursday that he anticipates more closures as the Delta variant keeps spreading. And with some mask and vaccine mandates already implemented, Murthy anticipates more will be added.
"The private sector is already stepping up to create verification systems," Murthy said. "What we are going to see more and more, Anderson, in the weeks and months ahead is, I believe, we're going to see more universities, more hospitals, more businesses, more retail establishments looking to put rules in place to require people to get vaccinated."
CDC document on Delta variant: 'The war has changed'
The study released by the CDC on Friday described 469 Massachusetts residents infected in a July outbreak in Barnstable County, which includes Provincetown. No deaths were reported among the residents.
About 74% -- or 346 cases -- had been fully vaccinated. Of those, 79% reported symptoms. Genetically sequenced cases revealed the Delta variant as the main culprit.
Meanwhile, the internal CDC document that said the variant appears to cause more severe infection advises that the agency should "acknowledge the war has changed."
It recommends vaccine mandates and universal mask requirements.
The CDC director confirmed the authenticity of the document.
"I think people need to understand that we're not crying wolf here. This is serious," Walensky told CNN.
The document says the Delta variant is about as transmissible as chickenpox, with each infected person, on average, infecting eight or nine others. The original lineage was about as transmissible as the common cold, with each infected person passing the virus to about two other people on average.
NC school system to require masks indoors
One of the most contentious issues across the country surrounds wearing face coverings in schools. Several areas announced Friday they would require or recommend masks, while Florida's governor, while signing an executive order, again said parents should make the decisions.
In North Carolina's most populous area, Mecklenburg County, which includes Charlotte, the school board voted for masks to be worn indoors.
"This decision aligns with local and state guidance, as well as national guidelines, which address the Delta variants of (coronavirus)," said Elyse Dashew, chairperson of the Charlotte-Mecklenburg Schools Board of Education, according to CNN affiliate WSOC. "The infection numbers in our county are cause for serious concern -- and significant precautions to protect our students and staff."
Only one of the board's nine members voted against the measure.
First grade student Daniel Cano, 5, and his mom, Sonia Cano, walk past Covid-19 safety precaution, social distancing and hand washing signs at a L.A. Unified "meet and greet" with its medical advisers.
In Massachusetts, schools will meet five days a week for in-person learning and masks are recommended for some people.
The state's Department of Elementary and Secondary Education said all students on buses should wear a face covering. It also recommended students in kindergarten through sixth grade should wear masks as should unvaccinated students in higher grades and all unvaccinated staff members.
In Kentucky, Gov. Andy Beshear urged schools to implement mask mandates for the upcoming academic year.
Beshear said that schools who do not mandate masks "will fail, and it will be the students who lose out on in-person learning that they would otherwise be in, and it's unprotected parents and grandparents that may pay a bigger price."
Kentucky's Department of Health, in light of the CDC's new guidance, recommends all people inside schools wear masks.
Florida Gov. Ron DeSantis has issued an executive order with emergency rules that prevent the implementation of mask mandates in schools.
DeSantis, who has been a vocal critic against the CDC's recommendations for masking in schools, doubled down on his position, stating there will be no lockdowns, school closures, restrictions, or mandates in his state.
The order was issued "to protect parents' freedom to choose whether their children wear masks," the governor said in a news release.
The executive order says the CDC's guidance "lacks a well-grounded scientific justification" while referring to a Brown University study the governor says found no correlation with Covid-19 data from schools and mask mandates.
After Miami-Dade County Public Schools announced it will reconsider its mask-optional policy, DeSantis, through his press secretary, hinted at calling a special session of the state Legislature to protect children against mask mandates.
"Many school boards are making the decision to go mask-optional, which is the right decision from our perspective. However, if Miami-Dade County Public Schools does decide to mandate masks, I'd just refer you back to Governor DeSantis' comments from the literacy presser last week: He hinted that the state legislature could do a special session to ensure a normal, mask-optional school year," spokesperson Christina Pushaw said in a statement to CNN.
Superintendent Alberto M. Carvalho said the district will announce its final decision on masks about two weeks before school starts on August 23.
Doctor: 'We're becoming victims of the unvaccinated'
Some states are seeing consequences unfold.
In Louisiana, a Baton Rouge medical center said that because it needs to divert staff to treat a crush of Covid-19 patients, it is de-prioritizing other care.
Our Lady of the Lake Regional Medical Center said this week it halted the scheduling of non-urgent surgical procedures that would require a patient stay.
"We're becoming victims of the unvaccinated," Dr. Christopher Thomas, a critical care physician at the medical center, told CNN's "Newsroom" on Friday.
"We currently are overwhelming our bed capacity. We're creating burnout for our teams. And honestly, we're beginning to impact the health care of the rest of the community," he said.
About 140 Covid-19 patients were at Our Lady of the Lake as of Thursday, 30 of whom had been admitted over the previous 24 hours -- the most since the pandemic began, according to a hospital spokesperson.
About 97% of the hospital's intensive-care patients Friday morning were unvaccinated, Thomas said.
Louisiana's vaccination rate is among the lowest in the country, with just 37% of residents fully vaccinated as of Thursday, according to CDC data.
In Hawaii, the governor is considering travel restrictions.
Since last month, travelers who are fully vaccinated have been able to take domestic flights to Hawaii without having to be tested for the coronavirus, with no restrictions between islands. The state went into a virtual travel lockdown in the early weeks of the Covid pandemic, costing the state hundreds of millions of dollars in tourism revenue.
State health director Dr. Libby Char said cases are rising and Gov. David Ige said it might be necessary to limit travel.
"I can assure you, at the point that I believe the hospitals have more patients than they would be able to handle, then we would take specific actions to restrict movements again," Ige said.
