Ten Florida school districts have adopted mask mandates for students this month.
The United States is facing a COVID-19 surge this summer as the more contagious delta variant spreads.
More than 634,000 Americans have died from COVID-19 while over 4.4 million people have died from the disease worldwide, according to real-time data compiled by the Center for Systems Science and Engineering at Johns Hopkins University.
Just 60.8% of Americans ages 12 and up are fully vaccinated against COVID-19, according to data from the Centers for Disease Control and Prevention.
The Pentagon on Wednesday announced mandatory Pfizer vaccinations, calling it "necessary to protect the safety of our service members and force."
Pentagon press secretary John Kirby said 68% of the active duty force is fully vaccinated and just over 76% have had at least one dose.
Pfizer's COVID-19 vaccine was granted full approval by the FDA on Monday.
-ABC News' Luis Martinez
Delta is raising health insurance premiums for unvaccinated employees by $200 a month to cover COVID-19 costs like potential hospitalization, which the airline says has cost it $40,000 per person on average.
In recent weeks, all Delta employees hospitalized with COVID-19 were not fully vaccinated, Delta CEO Ed Bastian wrote in a memo to employees.
Currently 75% of Delta employees are vaccinated, according to the airline.
The health insurance premium begins Nov. 1.
Unvaccinated employees will also have to wear masks indoors and be required to take a weekly COVID test beginning Sept. 12.
-ABC News' Mina Kaji
Moderna has finalized submission of its application to the Food and Drug Administration for full approval of its COVID-19 vaccine, the company announced Monday.
It's not yet clear how long the FDA will take to review Moderna’s application.
Pfizer completed its vaccine application in May and was granted full approval on Monday.
-ABC News' Eric Strauss
In the midst of a delta variant surge, a new study finds that giving a booster dose of the Johnson & Johnson shot six months after primary vaccination results in a nine-fold increase of a crucial antibody response, according to a company press release.
Meanwhile, a prior study found that people vaccinated with the Johnson & Johnson vaccine still had a durable immune response at least eight months later, even without a booster.
Collectively, the findings could help inform the U.S. government's recommendations about booster shots for the 14 million people who received the single-shot Johnson & Johnson vaccine.
Boosting after six months "appears to be safe, and boosts immune responses substantially," Dr. Dan Barouch, Ph.D., director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, told ABC News.
-ABC News' Sony Salzman
