Scientists in the United Kingdom reported this week that an experimental vaccine for coronavirus appeared to be working in human trials. But the early clinical trial involved only about 1,000 people. 

A much larger trial of a vaccine developed by U.S. pharmaceutical company Moderna, using 30,000 test subjects, is about to get underway, and about 1,000 people in San Antonio already have volunteered to test it. At least 300 will receive either a dose of the vaccine or a placebo in the coming weeks.

Clinical trials, which are research studies performed in people to evaluate a medical intervention such as a vaccine or drug, are the primary way that researchers find out if a new drug or medical device, for example, is safe and effective. A clinical trial also is used to determine the side effects of a treatment. 

Clinical Trials of Texas (CTT), located in the South Texas Medical Center, will conduct the trial for the Massachusett-based Moderna, which also will deploy similar trials in other cities. 

CTT has been recruiting since March for COVID-19 vaccine trials in San Antonio. Now CTT is lining up volunteers with the expectation that the Moderna trials will begin as soon as the company obtains approval from an institutional review board.

“This trial is designed for people who have not been exposed to the virus or tested positive for the virus,” said Dr. Douglas Denham, chief medical director at CTT. “They also have to be relatively healthy, be age 18 and up. We also want them to have certain risk factors.”

Those risk factors include occupation, he said, with CTT seeking out first responders and others who are in close contact with the general public and thus more likely to be exposed to the virus. A local pulmonologist has asked to participate in the trial, Denham said. “He’s exhausted – he’s been in the hospital for the last week just treating patients in the ICU,” Denham said. “These are the folks on the front lines – they want something to protect them.”

CTT is also looking to enroll elderly people and minorities in the trial. “[We’re] also looking for folks from our minority populations, which are not really represented in a lot of trials, but yet we’re seeing out there in the real world [minorities] contracting the virus in greater numbers than you would expect in terms of the population,” Denham said. 

He added that scientists need that information because there are slight variations in how different people respond to a virus or vaccine. 

San Antonio’s majority Latino population, high number of retirees, and its reputation in the medical research community, make it a desirable city to conduct clinical trials, Denham said. CTT has enrolled residents in 15 to 20 clinical trials evaluating treatments for everything from the flu and pneumonia to women’s health.

Participants are paid a “moderate fee” to compensate them for their time and travel expenses. “It’s not a huge amount of money,” Denham said.

But not every person who is accepted for the coronavirus vaccine trial will get the actual vaccine being developed by Moderna. A one-to-one randomization trial means that for every patient who receives the investigational vaccine, another receives a placebo – a substance that has no therapeutic effect.

The only people who will have the knowledge about who gets what are the scientists who designed the trial, Denham said. 

After a screening process, trial subjects will receive an injection and then later a second injection and will submit to follow-up appointments and monitoring phone calls for a two-year period. 

Roland Chabera isn’t worried about being stuck with a needle or any possible risks of the investigational vaccine. The 24-year-old high school teacher volunteered for the trial after hearing about it from a friend who works at CTT and hopes to be selected for the vaccine trial. 

“I’m not being injected with coronavirus or COVID-19 – it’s just to see how my body will react over the long term,” Chabera said. 

He’s motivated to participate because he knows that minorities tend to be the least likely to participate in such studies, he said. “Also the fact that I do have people in my circle who are [at much higher risk].”

Participating in the trial won’t put Chabera at any more or less risk of contracting the virus than anyone else. That was his main concern, he said, as he has been taking precautions against coming into contact with the coronavirus, particularly in order to protect his girlfriend’s grandmother. 

Denham said that, like the flu vaccine, the investigational coronavirus drug is not a live vaccine and won’t make people get sick with the virus, though there could be side effects caused by the body attacking the virus. 

“By injecting parts of the virus, it will elicit an immune response that will allow our immune system to detect these viruses, and trigger a response … and defeat the virus,” he said. “You don’t get ill from the virus or the injection itself.”

When people get the actual flu, he added, the reason they have fever, chills, and other symptoms is not because of the virus itself. “It’s your immune system trying to fight off infection,” Denham said. 

How will Denham and CTT know if the new trial vaccine is working?

“We will not be made aware of the results,” Denham said. “We’re ‘blind’ just like the patients will be.”

The study will continue over the course of several years, with scientists looking at whether antibodies against the virus are developing in response to the vaccine. 

Some trial subjects have asked whether they can get the actual vaccine once it is approved, Denham said. But he doesn’t know the answer to that and to many other questions that have been raised as scientists work at what the Trump administration has called “warp-speed” to find a vaccine against the deadly virus. 

“First, who’s going to make it? [and] who is going to be the first people to get the vaccine?” he said. “I’m sure they’re thinking about those [issues] at some level, but just because we have a vaccine … that doesn’t mean that it’s going to be miraculously available for everybody in the United States or around the world.”

Shari Biediger is the development beat reporter for the San Antonio Report.