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.
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
Several Paralympic athletes have tested positive for COVID-19 in Tokyo in recent days.
According to daily figures released by the Tokyo 2020 organizing committee, at least eight positive cases have been confirmed among unnamed Paralympic athletes so far, with two new cases reported on Wednesday following the opening ceremony.
The 2020 Summer Paralympics officially opened in the Japanese capital on Tuesday, after a yearlong delay due to the coronavirus pandemic. Like the 2020 Olympics, which ended on Aug. 8, this year's Paralympics is taking place under a state of emergency as Japan struggles with a growing COVID-19 crisis.
Leaders of the Orange County public school system voted Tuesday to require a mask mandate for all students and staff.
The rule goes into effect on Aug. 30 and will last for at least two months. There will be exemptions for medical reasons.
School board members cited the growing COVID-19 rates and hospitalizations in the area as the reason for their decision.
