A Florida school district that defied Gov. Ron DeSantis' ban on school mask mandates said Tuesday that two of its employees died from the virus last weekend.

Carlee Simon, the superintendent for the Alachua County Schools, said in a statement that the district "is experiencing this spike first-hand."

"Over the weekend two of our employees passed away from COVID," she said in a statement. "We've had 18 new cases in the last three days alone. More than 80 employees are now in quarantine, and that number is rising fast."

The school district, which includes which includes Gainesville, voted Tuesday night to issue a mask mandate for students and staff for the next two weeks. The mandate will be reevaluated on Aug. 17, Simon said.

The Hawaii State Department of Education announced that all middle and high school athletes, athletic staff and volunteers will need to be fully vaccinated by Sept. 24 in order to participate in activities.

The rule affects students who are eligible for the vaccines, meaning they must be over 12.

"This decision was not made lightly because we know the important role athletics play in a well-rounded education, but we cannot jeopardize the health and safety of our students and communities," interim Superintendent Keith Hayashi said in a statement.

The start of the athletic season was delayed to Sept. 24 due to the state's rising positivity rate, according to the department.

This is the first state to require vaccinations for its student athletes.

-ABC News' Bonnie McLean

Illinois Gov. JB Pritzker announced Wednesday that all pre-K through 12th grade schools and day cares must follow universal masking indoors regardless of vaccination status.

Pritzker said the state is facing a growing threat from the delta variant and noted that children under 12 aren't yet eligible for COVID-19 vaccines.

"Far too few school districts have chosen to follow the federal Centers for Disease Control and Prevention prescription for keeping students and staff safe," he said at a news conference. "Given the CDC’s strong recommendation, I had hoped that a state mask requirement in schools wouldn’t be necessary, but it is."

The latest delta surge is once again pushing hospital staffing to breaking points across the U.S.

In Alaska, Idaho, Oregon and Washington, some "facilities are experiencing substantial shortages of both clinical and support staff," according to a Department of Health and Human Services planning document obtained by ABC News Wednesday.

In hard-hit Missouri, many hospitals "don’t have the staff to support a surge without further modification to operational strategies," the document said.

At a Shreveport, Louisiana, hospital, where the number of COVID-19 patients are multiplying, nurse Melinda Hunt told ABC News, "To be honest, I probably cry most days at work. And I cry at home. I’m tired. I’ve been doing this a year and half. It feels like it’s never going to end."

A real-world study of South African health care workers found that the single-shot Johnson & Johnson vaccine was highly effective against the delta and beta variants, according to the South African Medical Research Council, which presented the results Friday.

The vaccine was between 91% and 96% effective against death, according the study, which included more than 477,000 health care workers. J&J showed stronger protection against the delta variant, now dominant in the United States and South Africa, than it showed against the beta variant.

"The data reported today by South African investigators show that a single shot can protect against death due to COVID-19 in the most challenging epidemiologic setting: A massive delta surge in Africa," said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, who helped invent the J&J shot but was not directly involved in the South Africa study.

While the results have not yet been published in a peer-reviewed journal, they may serve as a reassuring data point as the delta variant sweeps the U.S.

Glenda Gray, president and CEO of the South African Medical Research Council, who led the study, said at the Friday press conference that the J&J vaccine showed good durability, an indication that there's no need for booster shots just yet.

-ABC News' Sony Salzman.