Questions about COVID-19 Vaccines and Vaccine Trials?

Dr. Cindy Gay shares insight about the ins and outs of COVID-19 vaccine trials in this exclusive Q&A.

Dr. Cindy Gay stands outside a building on UNC-Chapel Hill's campus.

Dr. Cindy Gay shares insight about the ins and outs of COVID-19 vaccine trials in this exclusive Q&A.

Dr. Cindy Gay, primary investigator for Moderna’s COVID-19 vaccine clinical trial at UNC-Chapel Hill, shares insight about the ins and outs of COVID-19 vaccine trials in this exclusive Q&A.

Who better to test a potential COVID-19 vaccine than Cindy Gay?

Gay received her M.D. and M.P.H. at Carolina in 1998 and 1999, respectively, and is an associate professor of medicine in the UNC Division of Infectious Diseases and medical director of the UNC HIV Cure Center. She is one of Carolina’s leading infectious disease experts, with a background in a variety of HIV clinical and translational research.

At the onset of the global pandemic, infectious disease colleagues at Carolina and across the U.S. pivoted quickly and formed the COVID Prevention Network (CoVPN). The network coordinates multiple studies, including the current phase 3 clinical trial for ModernaOpens in new window’s mRNA-1273 COVID-19 vaccine. The overall goal of the national study is to enroll 30,000 volunteers and confirm the vaccine’s efficacy and safety.

Carolina is one of more than 90 sites testing the vaccine across the U.S. Gay is leading the study at UNC alongside a dedicated team of physicians, nurses, research specialists, pharmacists, medical assistants, data and project managers.

Recently, Gay took time out of her busy schedule to answer a few questions about the Moderna trial — and about vaccines and vaccine trials in general. To learn more about the trial and meet the rest of the clinical trial team, visit

Does the Moderna vaccine differ from other COVID-19 vaccines currently in trials?

This vaccine is similar to other COVID-19 vaccines in that it is an injection. Like some other COVID-19 vaccines currently undergoing trials, it involves two injections separated by about one month. The second, or booster, dose is not uncommon, as many approved vaccines include multiple doses, such as many childhood vaccination series, hepatitis B, MMR, HPV and others. The Moderna vaccine is a messenger RNA vaccine; there is one other COVID-19 vaccine using a similar vaccine strategy or platform.

Will a COVID-19 vaccine require annual vaccinations, like the flu vaccine, or will it be total immunity?

We don’t know yet. This is one of the things we hope to understand better from the current and upcoming COVID-19 vaccine studies.

Will everyone need the vaccine?

The degree to which any COVID-19 vaccine that is proven to be effective in preventing infection and severe COVID-19 disease would be mandated for certain occupations — such as health care workers — remains to be seen. There are many factors that would come into play. However, if we are lucky enough to have one or more COVID-19 vaccines that are proven to be safe and effective, the more people who receive the vaccine, the better the protection within families, across workplace settings and throughout communities. It’s important to understand that vaccines provide two potential benefits: to the individuals who receive the vaccine and to those around them.

Is it likely we’ll end up with more than one approved vaccine?

The early data for all of the vaccine candidates is promising, which is why the vaccines are being supported in phase 3 studies. The likelihood of having more than one approved vaccine is hard to predict, but we are certainly hoping that we will have more than one effective vaccine.

How do you ensure the vaccine is safe for trial participants?

It’s very important to understand that none of the COVID-19 vaccines currently being studied can cause infection with SARS-CoV-2. The vaccines include only one protein that makes up the SARS-CoV-2 virus, and thus there is no risk of exposing anyone to the virus through vaccination. All of the vaccines moving into phase 3 studies have already been tested in earlier animal studies, as well as in phase 1 and phase 2 studies in humans. To move into phase 3 studies, there is a review to determine that there are no safety concerns from the earlier studies. The COVID-19 vaccine studies will carefully follow participants for any side effects from the injection, and this safety data is collected and reviewed on an ongoing basis.

Once a vaccine is approved, how do you deploy it in an equitable way?

When faced with a public health need for which the supply cannot meet the immediate demand, we will rely on individuals with expertise in ethics, public health, epidemiology and many other disciplines. These experts will determine how to prioritize vaccination to those at highest risk for infection and severe illness and those who are crucial to maintaining our day-to-day functioning. There will be more to come on this, but how to deploy an effective and safe vaccine is currently being planned.

Was it hard to recruit for diversity in the trials?

There is a challenge to reaching out to those who are at the highest risk, working in essential jobs and in close contact with others. By virtue of the fact that many of those at risk have to keep working, and many of these individuals are also caring for family members and/or trying to oversee remote learning for their children — they don’t have the time or luxury to learn of opportunities to participate. Many in the community are wary of COVID-19 vaccines that are not yet approved or the appearance that these studies are happening too fast. Misinformation and lack of trust does make it more difficult to recruit across the populations who have been most impacted by COVID-19. The benefits of vaccines and the fact that we would not have any chance of an effective COVID-19 vaccine without the coordinate effort is not being heard by everyone.

What is the predicted cost for individuals to receive the vaccine?

There is no cost to participants in a study for a COVID-19 vaccine. The cost of a vaccine when approved and clinically available will have to be determined, but I anticipate it will be either free or covered by insurance for those who have it, given how important the health benefit would be and the overall public health benefit.

If this trial is successful, what happens next?

The hope is that many of the COVID-19 vaccines will be found to be effective and lead to immediate large-scale manufacturing so that doses are made available to all willing to receive them. Given the potential benefit and the incredible need, plans for allowing safe manufacturing of effective vaccines are already underway. Plans for how to deploy an effective vaccine will likely occur in a tiered strategy, with the most at risk for infection and severe disease offered the vaccine first, followed by offers to those at less risk when more vaccines are produced and available.

How does one volunteer to participate in a COVID-19 research trial?

We are looking for individuals who are at increased risk for COVID-19, so those who have frequent contact with others due to work or life circumstances, or who are living with someone who does. Those interested in participating in COVID-19 research may share their interest by registering online at coronaviruspreventionnetwork.orgOpens in new window. By entering the UNC site code, CHNC, their information is directed to the UNC research team.

They can also visit in new window to explore other studies.

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