Just 1,345,064 travelers were screened at U.S. airports on Tuesday, the lowest since May 18 when 1,408,017 were screened, the TSA said.

United CEO Scott Kirby said Monday he thinks holiday travel will return to normal.

-ABC News' Sam Sweeney

San Diego has become the first county in the U.S. to declare that health misinformation is causing a public health crisis in its community. This follows the County Board of Supervisors' 3-2 vote Tuesday night.

Changes to county strategy to combat the pandemic will include: labeling health misinformation and providing timely health information to counter it; modernizing public health communications; investigating in digital resources and training for health practitioners and health workers; and developing a website to be a central resource for fighting health misinformation.

The new policy was introduced when 96.7% of hospitalizations in San Diego County were residents who were not fully vaccinated.

KISS co-lead singer Gene Simmons tested positive for COVID-19, the band shared on its Twitter page Tuesday evening.

In a statement, the band said the 72-year-old was experiencing "mild symptoms."

His diagnoses comes less than a week after co-lead singer Paul Stanley, 69, tested positive for COVID-19 as well.

In a statement released on Aug. 26, the band said that, "everyone on the entire tour, both band and crew, are fully vaccinated."

KISS has postponed four of its "End of the Road" tour shows from Sept. 1 to Sept. 5.

"The band and crew will remain at home and isolate for the next 10 days," the band said in a statement.

Peter Marks, the director of the Food and Drug Administration's Center for Biologics Evaluation and Research (CBER), announced the upcoming departure of two top vaccine regulators to his staff in an internal memo, which was obtained by ABC News.

Dr. Marion Gruber, director of the FDA's Office of Vaccines Research and Review (OVRR) and her deputy, Dr. Phil Krause, are set to leave the agency in October and November respectively, according to the memo.

Krause, who's been with the agency for over a decade, and Gruber, who has been with the FDA for over 30 years, were instrumental in the review and authorization of the three COVID-19 vaccines, the memo said.

The memo said that Gruber will be "retiring" and gave no other details about Krause's departure.

ABC News has reached out to both Gruber and Krause for comment.

When reached for comment about their departure, an FDA spokesperson told ABC News the agency is "confident in the expertise and ability of our staff to continue our critical public health work, including evaluating COVID-19 vaccines."

Their departures come at a critical time for the vaccine review team. After facing pressure to move as fast as possible to get vaccines' full licensure done, the agency is now weighing booster shots for a wider pool of Americans.

The timing of the booster shot approval has been a bone of contention amongst federal agencies after the Biden administration announced the availability of booster shots would begin ahead of any ruling from the FDA or Centers for Disease Control and Prevention advisory groups.

-ABC News' Sasha Pezenik

Florida Gov. Ron DeSantis filed an appeal against a court ruling invalidating his ban on student mask mandates Thursday evening.

The governor had banned school districts from implementing mask mandates without a parent opt-out.

The move unleashed a stay of proceedings that enables the state to continue punishing districts, at least until Wednesday, when a judge will decide whether to vacate the stay.

In the meantime, school board members across the state could continue to lose their salaries if their schools set mask mandates -- a punishment given to board members in two counties and threatened to those in eight others.

The appeal comes a week after Judge John C. Cooper found that a blanket ban on face masks in schools "does not meet constitutional muster.”

-ABC News' Will McDuffie