Nearly 350 children are currently hospitalized with COVID-19 in Texas, state data shows.

According to the Texas Department of State Health Services' online COVID-19 dashboard, which was last updated on Sunday afternoon, there are 345 pediatric patients in hospitals across the Lone Star State. That number was up from 282 on Thursday afternoon.

The data also shows there are 73 staffed pediatric intensive care unit beds available in all of Texas.

Since the new school year began in Texas last month, some 52,000 students have tested positive for COVID-19, according to the data.

-ABC News' Gina Sunseri

Booster shots for the Moderna vaccine will have to wait at least one week after the president's Sept. 20 target because of the delay in submitting data, Dr. Anthony Fauci said Sunday.

Fauci told CNN that Pfizer was able to submit its data to the Food and Drug Administration about their mRNA vaccine booster shot earlier, and "it's been examined and ready to go." Moderna is behind in submitting its data causing the delay.

"What you might see is rather than the simultaneous rolling out of the booster program of both those products you may have be sequential by about a week or two," he said. "I don't think that is a major issue there, but we would have liked to have seen it happen all together simultaneously."

Three Florida school districts have filed a legal challenge against the state health department, seeking to invalidate an emergency rule that allows parents to opt out of mask mandates.

The petition, filed Friday, argues that the emergency rule -- issued after Gov. Ron DeSantis ordered the health department to protect parents' choice when it comes to masking their children -- exceeds its authority and is invalid.

The school districts in Alachua, Broward and Orange counties, which all require students and staff to wear masks, requested that an administrative judge hear the case.

Florida's education commissioner has withheld the salaries of school board members in Alachua and Broward counties over their mask mandates -- and has threatened similar action in Orange County.

Last week, a Tallahassee judge ruled in favor of a group of parents who sued the state over its ban on mask mandates. That ruling is being appealed.

-ABC News' Will McDuffie

Over 2.1 million people were screened at U.S. airport security check points Friday -- the highest checkpoint volume since Aug. 15, Transportation Security Administration spokesperson Lisa Farbstein said. 

Americans have flocked to airports to travel for the Labor Day weekend despite the threat of the delta variant and surging COVID-19 cases and hospitalizations.

The U.S.’ daily case average remains around 153,000 cases a day, up by approximately 964% in the last two months. 

Overnight Friday, the U.S. recorded its second single-highest day of COVID cases this week with more than 170,000 new cases reported.

Every state in the country is currently experiencing high community transmission. The South still leads the country with the highest case rates. Tennessee, and South Carolina currently have the country's highest case rate, followed by Mississippi, Florida, Georgia and Wyoming, all with case rates above 600 per 100,000 people.

-ABC News' Ahmad Hemingway and Arielle Mitropoulos

Authorities are warning of a fresh and specific increase in counterfeit COVID-19 vaccination cards on the online market, according to a new law enforcement bulletin obtained by ABC News.

A blank template imitating the CDC-issued COVID-19 vaccination record card has been circulating on various social media platforms, including an anti-vaccine Telegram channel, the internal notice says. 

These blank cards can be downloaded, printed and filled out in order to gain entry where proof of vaccination is required, and to "satisfy employer vaccine mandates," according to the notice.

This latest warning comes just as ABC News has reported exclusively that federal health officials are seeing an alarming rise in the demand for these fraudulent cards, which cyber experts and federal officials are are concerned is a burgeoning and rapidly evolving market.

The illicit niche industry for forged cards is hitting its stride just as new vaccine requirements are rapidly being implemented at the federal, state and local levels and in both the public and private sectors -- requiring proof of inoculation in order to work at a hospital, teach or attend school, work out at the gym, or eat inside a restaurant.

Despite new policies and FDA full approval of Pfizer's COVID-19 vaccine, some hesitant Americans still refuse to be vaccinated.

For enterprising fraudsters, the fresh demand presents a ripe opportunity. 

In this latest bulletin, social posts and law enforcement source information indicate that criminal actors in the Philadelphia area are "profiting from the production of these cards" and "selling the counterfeit cards through online and in-person sales."

"The PDF being shared on local Telegram channels offers limitless access to counterfeit vaccination cards," authorities warn. 

"The use of fraudulent cards may have a significant impact on public health, especially in compact and vulnerable communities like academic institutions and healthcare facilities," the bulletin warns, reminding those who profit from or use these fake cards may face prison time or hefty fines. 

-ABC News’ Aaron Katersky and Sasha Pezenik