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Vaccines stimulate the immune system to produce immune responses that protect against infection. Vaccines provide a safe, cost-effective and efficient means of preventing illness, disability and death from infectious diseases. Vaccines have saved millions of lives worldwide and dramatically reduced the prevalence of many life-threatening infectious diseases. There remains a need for new and improved vaccines against existing infectious diseases (like COVID-19).
Credit: National Institute of Allergy and Infectious Disease.

Vaccine Basics: This graphic outlines how vaccines can help the body learn to identify a new virus, and help the body remember how to fight the virus if a person is exposed to it in the future.
Credit: Nik Spencer/Nature

An antibody is a Y-shaped protein produced by B cells, which are part of the immune system. There are several different kinds of antibodies, and typically vaccines are designed to produce the antibodies that recognize and “tag” viruses as foreign invaders by binding to unique parts of a virus. Antibodies that bind to the surface of a virus and block entry into a person’s cells can actually prevent infection or disease: this is called neutralization. These antibodies, which occur naturally in some people after vaccination or infection, can be copied in the lab and then given to people as a prevention option or treatment. The term “monoclonal” refers to these laboratory-made antibodies.

The development of monoclonal antibodies for prevention of COVID-19 is important for a number of reasons, including:

1. Monoclonal antibodies may be able to serve as another prevention option until a vaccine is available.
2. Monoclonal antibodies may be able to provide immediate protection or treatment for those who are exposed and not yet vaccinated.
3. Monoclonal antibodies may be required for people who cannot develop or maintain an adequate immune response after vaccination, such as older adults.

In traditional research, people get a vaccine and scientists wait to see if their bodies will respond to the vaccine by making antibodies against the virus. In antibody studies, that step is skipped and people receive the antibodies directly, using intravenous infusions, commonly known as “getting an IV,” with shots into the skin or infusions under the skin. Another difference is that antibodies produced naturally by your body in response to a vaccine can last for a long time, but these laboratory-made antibodies usually only last for a few months, thus requiring people to get multiple infusions or injections on a regular schedule.

Antibodies help prevent infection. Most vaccines stimulate the body to make antibodies. If you get a SARS-CoV-2 vaccine, your body will likely develop antibodies to the virus. Because of this, some antibody-based tests for SARS-CoV-2 infection may return a positive result even if you are not, or were not previously, infected with SARS-CoV-2. This is called a vaccine-induced seropositivity (VISP) test result.

Two Kinds of Tests Are Available for SARS-CoV-2

• A viral test tells you if you have a current SARS-CoV-2 infection. This test detects the presence of the actual virus in your body. Some of these tests are referred to as PCR tests. A nasal swab or saliva sample is usually needed for this test.
• An antibody test tells you if you had a previous infection. A sample of blood is needed to determine if your body has developed antibodies to SARS-CoV-2.

Right now, VISP shouldn’t be a problem because the antibody tests that are widely used (either the Abbott or Roche antibody tests) do not detect the type of antibody produced by the current vaccines being developed. Instead, they pick up on a different antibody produced by a natural infection with SARS-CoV-2. However, this could change in the future as new antibody tests are developed.

Your body will make different antibodies in response to SARS-CoV-2 infection than in response to vaccination.

One of these antibodies is called a “spike antibody,” meaning that the antibody is directed at the spikes that surround the virus’s outer shell. The antibody attaches itself to the spikes on the virus in order to prevent the virus from attaching to your body’s healthy cells and causing infection. These are the types of antibodies that vaccines aim to teach your body to make in order to protect against infection.  

Natural infection with SARS-CoV-2 will produce different antibodies. These antibodies can bind to not just the spike, but also to other viral proteins such as the nucleocapsid. Current vaccines in development do not lead to antibodies against the nucleocapsid protein.

The Abbott and Roche antibody tests currently in use will only detect the second type of antibody that is produced by a natural infection with SARS-CoV-2. As time goes on and more vaccine candidates are tested, however, new antibody tests might be developed that also detect antibodies that binds to the virus’s spikes. If this happens, it means you could get a positive antibody test result, even if you have never been infected with SARS-CoV-2. Health care providers may not interpret your test results correctly as an immune response to a vaccine; they may incorrectly see it as an indication of prior infection with SARS-CoV-2. Once an effective vaccine is found and widely administered to the public, testing technology will need to clearly distinguish between vaccine responses and infection.

Clinical research is medical research that involves people like you. When you volunteer to take part in clinical research, you help doctors and researchers learn more about disease and improve health care for people in the future. Clinical research includes all research that involves people.

Types of clinical research include:

• Epidemiology, which improves the understanding of a disease by studying patterns, causes, and effects of health and disease in specific groups.
• Behavioral, which improves the understanding of human behavior and how it relates to health and disease.
• Health services, which looks at how people access health care providers and health care services, how much care costs, and what happens to patients as a result of this care.
• Clinical trials, which evaluate the effects of an intervention on health outcomes.

The goal of clinical trials is to determine if these treatment, prevention, and behavior approaches are safe and effective. People take part in clinical trials for many reasons. Healthy volunteers say they take part to help others and to contribute to moving science forward. People with an illness or disease also take part to help others, but also to possibly receive the newest treatment and to have added (or extra) care and attention from the clinical trial staff. Clinical trials offer hope for many people and a chance to help researchers find better treatments for others in the future.

The idea for a clinical trial often starts in the lab. After researchers test new treatments or procedures in the lab and in animals, the most promising treatments are moved into clinical trials. As new treatments move through a series of steps called phases, more information is gained about the treatment, its risks, and its effectiveness.

Clinical trials are conducted in a series of steps called “phases.” Each phase has a different purpose and helps researchers answer different questions.

• Phase I trials: Researchers test a drug or treatment in a small group of people (20–80) for the first time. The purpose is to study the drug or treatment to learn about safety and identify side effects.
• Phase II trials: The new drug or treatment is given to a larger group of people (100–300) to determine its effectiveness and to further study its safety.
• Phase III trials: The new drug or treatment is given to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it with standard or similar treatments, and collect information that will allow the new drug or treatment to be used safely.
• Phase IV trials: After a drug is approved by the FDA and made available to the public, researchers track its safety in the general population, seeking more information about a drug or treatment’s benefits, and optimal use.

Most clinical trials pose the risk of minor discomfort, which lasts only a short time. However, some study participants experience complications that require medical attention. In rare cases, participants have been seriously injured or have died of complications resulting from their participation in trials of experimental treatments. The specific risks associated with a research protocol are described in detail in the informed consent document, which participants are asked to consider and sign before participating in research. Also, a member of the research team will explain the study and answer any questions about the study. Before deciding to participate, carefully consider risks and possible benefits.

Potential benefits: Well-designed and well-executed clinical trials provide the best approach for you to:

• Help others by contributing to knowledge about new treatments or procedures.
• Gain access to new research treatments before they are widely available.
• Receive regular and careful medical attention from a research team that includes doctors and other health professionals.

Potential Risks to taking part in clinical trials include the following:

• There may be unpleasant, serious, or even life-threatening effects of experimental treatment.
• The study may require more time and attention than standard treatment would, including visits to the study site, more blood tests, more procedures, hospital stays, or complex dosage schedules.

Ethical guidelines

The goal of clinical research is to develop knowledge that improves human health or increases understanding of human biology. People who take part in clinical research make it possible for this to occur. The path to finding out if a new drug is safe or effective is to test it on patients in clinical trials. The purpose of ethical guidelines is both to protect patients and healthy volunteers, and to preserve the integrity of the science.

Informed consent

Informed consent is the process of learning the key facts about a clinical trial before deciding whether to participate. The process of providing information to participants continues throughout the study. To help you decide whether to take part, members of the research team explain the study. The research team provides an informed consent document, which includes such details about the study as its purpose, duration, required procedures, and who to contact for various purposes. The informed consent document also explains risks and potential benefits.

If you decide to enroll in the trial, you will need to sign the informed consent document. You are free to withdraw from the study at any time.

IRB review

Most, but not all, clinical trials in the United States are approved and monitored by an Institutional Review Board (IRB) to ensure that the risks are minimal when compared with potential benefits. An IRB is an independent committee that consists of physicians, statisticians, and members of the community who ensure that clinical trials are ethical and that the rights of participants are protected. You should ask the sponsor or research coordinator whether the research you are considering participating in was reviewed by an IRB.

Only through clinical research can we gain insights and answers about the safety and effectiveness of treatments and procedures. Groundbreaking scientific advances in the present and the past were possible only because of participation of volunteers, both healthy and those with an illness, in clinical research. Clinical research requires complex and rigorous testing in collaboration with communities that are affected by the disease. As research opens new doors to finding ways to diagnose, prevent, treat, or cure disease and disability, clinical trial participation is essential to help us find the answers.