Two trials for COVID-19 vaccines being done in Austin are coming to a critical point, and one is even expanding to include more people.


The Pfizer Inc. trial being conducted by Austin Regional Clinic’s clinical research center has 200 adult patients enrolled and is expanding to teens ages 12 to 17 in November.


Dr. Gretchen Crook, the principal investigator for ARC Clinical Research, said it is typical for studies to start with adults and then add teens or children. The data collected for adults doesn’t automatically translate to children, she said.


Benchmark Research enrolled 405 adults for the the Moderna trial in Austin.


In both trials, half of the participants receive the vaccine and half receive a placebo. Each group receives one injection and then a second injection about a month later. Participants and most of the researchers do not know who is in which group.


All of the people enrolled in the Moderna trial in Austin have received both injections. In the Pfizer trial, about two-thirds have received both injections.


Both trials are in Phase 3, the final phase of testing. Nationally, Moderna has 30,000 people in its trial. Pfizer has 45,000 people. They are two of the seven vaccine trials being supported by the federal government.


November is going to be a key time for the Moderna trial, Benchmark CEO Mark Lacy said. This is the month when researchers think they will have 150 cases of COVID-19 among the 30,000 participants. That 150 number will help show whether the vaccine made a difference statistically. Researchers are looking at the rate of COVID-19 infection among people who got the vaccine verses the rate of infection for people who received the placebo.


"Some people who got the placebo are going to get sick," Lacy said. "If a bunch of those people getting the actual vaccine — if they are also getting sick — that’s not a good result."


That would indicate the Moderna’s vaccine is not effective, and Moderna would not be able to go the FDA for emergency use authorization.


November is also key because the FDA wants participants to be followed for at least two months after receiving the second injection, which for the Moderna trial would be the end of November, Lacy said.


He said if the results coming out of November look promising, Moderna can go to the FDA in early December.


Both of the trials were looking for health care workers and essential workers to participate. The Moderna trial also was looking for people age 65 and older. That trial did not rule out things such as diabetes, obesity and HIV status.


"They were really looking for the average Joe," he said.


Both companies were also looking for minorities in their trials.


"There was a really big push to mirror the diversity of the United States," Crook said.


For the teens Crook is now trying to enroll in the Pfizer trial, they do not have to be current patients of ARC, but they need to have some risk of being exposed to the virus. That can include going to school, leaving the house or having family members who work outside of the home. The teens also cannot have other significant medical problems.


The participants of both trials are followed for two years and receive financial compensation for their time and travel. If the vaccine becomes approved by the FDA, the companies will then try to vaccinate the people who received the placebo.


In addition to logging coronavirus symptoms, the participants in both studies are making note of other symptoms to help researchers find any patterns of side effects. Those symptoms could be anything from allergies to urinary tract infections.


"We report everything," Crook said. "Whether we think it’s related or not."


The Moderna study results in one medical visit a month on average, Lacy said.


To enroll a child in the Pfizer teen study, parents or guardians can call 512-225-5931 or go to ARCclinicalresearch.com.


Having multiple vaccine trials is a good thing, Lacy said, because it’s unlikely that one company could produce enough vaccines to cover all of the need in the United States and other parts of the world.


The hope is that it will be like the flu shot with multiple companies offering a vaccine.