Where do vaccine trials for kids stand in Houston?

HOUSTON, Texas (KTRK) -- The Centers for Disease Control and Prevention reversed course Tuesday on some masking guidelines, recommending that even vaccinated people return to wearing masks indoors in parts of the U.S. where the coronavirus is surging.

Citing new information about the ability of the delta variant to spread among vaccinated people, the CDC also recommended indoor masks for all teachers, staff, students and visitors to schools, regardless of vaccination status.

In Texas, there is not a mask mandate in place. Gov. Greg Abbott issued an executive order prohibiting any public entity, including public schools, from mandating masks.

READ ALSO: Gov. Greg Abbott says he won't impose new mask mandate despite increasing COVID-19 cases

"We could still be a cause of transmission or infection to others and masking, as the American Academy of Pediatrics has indicated for everybody, including those who are vaccinated as you go back to school, is one of the immediate measures that we have in place to be able to prevent this transmission," said Dr. Flor Munoz with the Baylor College of Medicine.

School districts including Katy and Houston ISD have said they will allow students to wear masks if they chose to do so if their parents say it's OK.

Since the Houston area has seen a surge in COVID-19 cases, Harris County Public Health said it's seen a big increase in adolescent vaccinations over the past several weeks.

Children younger than 12 are not able to get the vaccine yet, but there are clinical trials underway in Houston.

Texas Children's Hospital is participating in the Pfizer trials for children and the Baylor College of Medicine is participating in the Moderna trial for kids starting with babies who are six months old up to 12-year-olds.

The big emphasis is on school-aged children, ages five to 11.

Researchers are looking at what dose to give kids. They are also looking at efficacy and antibody levels.

"We look at antibodies that babies and children can make after two doses of the vaccine and compare that with levels that are achieved with adolescents and adults," said Munoz. "It's amazing. What I can tell you is that children are wonderful in terms of their immune system really being able to respond."

Moderna told ABC News it's expanding its trial size to provide larger safety database.

READ MORE: Moderna expanding kids COVID-19 vaccine study to better assess safety

The New York Times is reporting Pfizer is also expanding its trial size for the same age group. That means we could see a vaccine for kids who are five to 11 years old by the end the year.

It's unclear if expanding the size of the children trials could delay that or not.

For updates on this report, follow ABC13 reporter Marla Carter on Facebook,Twitter and Instagram.