More than 32% of Travis County residents over the age of 16 have received at least one dose of the COVID-19 vaccine. However, officials have said the area will not be able to reach herd immunity, or the threshold at which it becomes hard for the virus to spread, until children are also able to be vaccinated.

So far, the vaccines being distributed in Texas have only been approved for emergency use in adults—those age 16 and older for the Pfizer vaccine and age 18 and up for the Moderna and Johnson & Johnson vaccines. That could be changing soon.

On March 31, Pfizer announced the results of a trial that showed its vaccine had 100% efficacy in participants ages 12-15. Albert Bourla, the chair and CEO of the drug company, said in a release Pfizer plans to submit the data to the U.S. Food and Drug Administration as a proposed amendment to its emergency use authorization that could pave the way to expand distribution to younger recipients.

Dr. Mark Escott, the Austin-Travis County interim health authority, said March 31 in a media conference the results could lead to children in the area getting vaccinated over the summer before school resumes in the fall.

"There's more work to be done, but these are promising results, particularly for middle school and high school students," Escott said. "It gives us enough time to ramp up vaccination to reach those groups to make it much safer in the fall for the return to more regulated in-person education."

Austin ISD has announced it will return to traditional, face-to-face instruction this fall while retaining a virtual option for families.

The exact target for herd immunity varies based on how quickly the virus is spreading locally and other factors, but federal health officials have said it will lie somewhere between 70%-90% of the overall population being vaccinated.

In addition to vaccinating children, Escott said the challenge to reach that threshold will be making the vaccine more available in places people already go as part of their daily routines such as grocery stores, doctor's offices and pharmacies, rather than making individuals sign up at a mass vaccination site through Austin Public Health or another local public health provider. As supply continues to increase, Escott said he expects to see the Texas Department of State Health Services increase its allocations to private providers such as H-E-B and CVS to reach people more easily.

"I think generally speaking we’re on a good timeline [U.S. President Joe Biden] set to have vaccine available to everybody who wants it by the end of May. Children will be another benchmark. It will probably be sometime over the summer for them," Escott said.

While everyone over the age of 16 is eligible to receive a vaccine in Texas as of March 29, APH has not yet opened availability beyond the initial groups who qualified: health care workers, teachers and school staff, residents over age 50 and those with underlying conditions. That is because officials said there are still too many people eligible in APH's system waiting to get a vaccine.

The system will open up to all adults when the waiting list thins out, officials said, and until then residents should seek the vaccine from other providers in the county or the surrounding area. Any Texas resident can sign up for a vaccine through any provider in the state; appointments are not limited by county of residence.