Frequently Asked Questions About COVID-19 Vaccine Studies

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Scientists are working hard to create a vaccine to prevent COVID-19, as it is our best hope for protecting people from infection and ending the pandemic. Right now, there are no vaccines to protect against COVID-19 approved for widespread use.

Creating a COVID-19 Vaccine That’s Safe and Effective

Vaccine development can take many years. Luckily, scientists can use past research on coronavirus vaccines -- like SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome) – to move quickly on a COVID-19 vaccine. To make sure it is effective for a large population, scientists have to:

  • Make sure the vaccine is safe. It must be tested thoroughly and in large numbers of people to make sure it is safe for humans.
  • Ensure the vaccine provides long-term protection. Sometimes, people can be re-infected with the same coronavirus months or years later. Most of the time, this only happens in a small number of people and symptoms are mild. An effective vaccine against COVID-19 will need to give people long-term protection from infection.
  • Protect the elderly. People over age 50 are at higher risk of severe COVID-19 symptoms. And, older people don’t typically respond as well to vaccines as younger people. A good COVID-19 vaccine will need to work well in older adults.
  • Research is a process that involves a degree of trial and error – researchers design a study based on what they believe the answer to a scientific question is, but they also have to be prepared for that answer to be wrong.  It can be confusing and frustrating, and may slow down the development of an effective vaccine.
  • An approved vaccine takes time to produce and distribute. It is possible that people will need two doses before they start to develop immunity to the virus.

Around the world scientists and regulators are working together to make sure we have the technology needed for mass production so that an approved vaccine will be available for billions of people as quickly and safely as possible.

COVID-19 Clinical Trials Directory

View all COVID-19 clinical trials currently enrolling or about to enroll through Duke investigators.

Frequently Asked Questions

Is Duke currently participating in any COVID-19 trials?
You can view COVID-19 trials at Duke that are currently enrolling on the Duke Clinical Trials Directory and searching for COVID-19 studies.

How do I find a COVID-19 vaccine trial?
Visit or the COVID-19 Prevention Network for information. You can also visit the Duke Clinical Trials Directory and search for COVID-19 studies.

Does a vaccine against COVID-19 already exist?
There is no licensed vaccine against the virus that causes COVID-19. Scientists are working very hard to develop a vaccine and conduct research to learn if one or more is safe and effective in preventing COVID-19 infections.

Don’t antibodies offer protection from COVID-19?
Antibodies are part of the body’s defense system, protecting you from invaders like bacteria, viruses and parasites. Antibodies “recognize” invaders (like viruses), marking them for destruction by other parts of your immune system.

We develop antibodies in response to an infection, including COVID-19. However, if you have COVID-19 antibodies, we don’t yet know how long they stay in your system or whether past infection protects you from getting infected again.

Will I get COVID-19 if I participate in a trial?
No. None of the vaccines will infect you with COVID-19. We also won’t expose you to or give you COVID-19 after the vaccinations. However, some people in the trial may test positive for COVID-19 just from being out in the community, not from the vaccine itself.

How will the scientists know if the vaccine is effective?
The studies use a design known as “randomized, double-blinded, placebo-controlled clinical trials.”  This means that some people in the study will get the vaccine, and some will get a placebo (sterile salt water that does not have any vaccine in it).

The vaccine and the placebo will appear identical, so neither the volunteers nor the study doctors will know who receives the vaccine and who receives the placebo. This is what we mean by “blinded.” To ensure the safety of the participants, the research pharmacist, who is not a study volunteer or a study doctor, keeps a “code book” to record who received the vaccine and who received the placebo. The research pharmacist only uses this information in case of an emergency to protect the participant (for instance, symptoms of an allergic reaction).

During the study, the researchers will compare the numbers of participants who have taken the vaccine who test positive or get sick to the number of participants who have taken the placebo who test positive or get sick. If the vaccine is effective, the number of participants who receive the vaccine and who test positive or get sick with COVID-19 will be significantly lower than the number of participants who receive the placebo and who test positive or get sick with COVID-19.

Why is it important to have a diverse group of participants in our vaccine trials?
We want to make sure that the vaccines we produce work for everyone. In order to do this, we need to make sure that people from all walks of life are included in our study. This will help us make sure that we know the vaccine is safe and effective for all the people who are receiving it.

COVID-19 has been particularly devastating to both Black and Hispanic/Latino(x)* people. Too often, Black and Hispanic/Latino(x) populations are vastly underrepresented in clinical research in the U.S. It is important to ensure that the people who have been most impacted by the virus are participating in innovative research that can get them treatment faster.

*Latino(x) = The terms Hispanic and Latino have been used interchangeably for the past 10 years. In recent years, the term Latinx is increasingly preferred to signal gender inclusivity, especially among younger Hispanic/Latino populations.

Do I have to join a COVID vaccine study?
No. You can say yes or no when asked to join any study. All study volunteers must go through a process called informed consent. It makes sure volunteers understand the following about the study:

  • What will happen in the study.
  • The risks and benefits of being in the study.
  • Any alternatives to being in the study.
  • Participation is voluntary. You may stop being in the study at any time without losing any of your rights or benefits or being penalized in any way.
  • How your privacy will be protected if you join the study.
  • Payment and medical treatment options if you are injured by the study.
  • Who to contact for questions and concerns about the study.

The study team takes great care to make sure you fully understand the study before you decide whether to join. All studies follow U.S. federal research regulations. All studies are also reviewed by the Duke University Health System Institutional Review Board to ensure volunteer safety and that the benefits of being in the study outweigh the risks.

All National Institutes of Health (NIH) funded studies include the use of a Certificate of Confidentiality that protects the privacy of all participants by not allowing any disclosure of identifiable, sensitive research information to anyone not connected to the research, except in very special circumstances. Studies funded by other organizations may also use a Certificate of Confidentiality.

Does a person have to test positive for COVID-19 to be in a COVID-19 vaccine or antibody study?
No. The vaccines and antibodies being tested in these studies aim to prevent a person from getting COVID-19. They must be tested on volunteers who do not have COVID-19 because our goal is to keep people healthy. Other studies of treatments may be offered to people who already have COVID-19.

Are vaccines safe?
Vaccines can cause side effects like a sore arm, low-grade fever, muscle aches and pains. However, they usually go away after a day or two. The value of protection for vaccinated people and the public has made vaccine development one of the top public health activities in our history, second only to a clean water supply.

Will COVID-19 vaccine participants get paid?
People who join a study often get paid for their time, transportation costs, and inconvenience. The amount per visit varies depending on the length of the visit and the procedures that take place. The details about payment will be explained when a person goes through the informed consent process to join a study.

How can I join a COVID-19 Vaccine Study?
You can join the Duke Vaccine Trials Unit Vaccine Research Volunteer Registry. A registry is a list (database) of people who have agreed to be contacted about research studies they may be interested in or qualify for. 

What do I have to do as a vaccine study participant?
Vaccine studies usually involve a series of screening and consent visits. You will come to the clinic to receive your doses of the vaccine or placebo. You may also have to give some blood samples and/or nasal swabs, answer surveys and tell the study team about any symptoms you are having and medications you are taking.

Learn More About Clinical Trials at Duke
Contact the Duke Recruitment Innovation Center