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  1. Development & Approval Process (CBER)

Vaccine Development – 101

Bottle of vaccine with syringe inserted


The U.S. Food and Drug Administration (FDA) is the regulatory authority that has oversight of the safety, effectiveness and quality of vaccines that are used in the United States.

Vaccines to prevent infectious diseases are given to millions of babies, children, adolescents and adults and it is critical that they are demonstrated to be safe and effective. Vaccines have prevented countless cases of disease and disability and have saved millions of lives. Ensuring the safety and effectiveness of vaccines is one of FDA’s top priorities.

FDA’s Center for Biologics Evaluation and Research (CBER) ensures that FDA’s rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines. Vaccine development is a complex science. FDA’s scientific and regulatory advice to vaccine developers, as well as FDA’s evaluation to determine the safety and effectiveness of vaccines, are among the most robust in the world.

How Vaccines Work

Vaccines work by mimicking the infectious bacteria or viruses that cause disease. Vaccination stimulates the body’s immune system to build up defenses against the infectious bacteria or virus (organism) without causing the disease. The parts of the infectious organism that the immune system recognizes are foreign to the body and are called antigens. Vaccination exposes the body to these antigens.

Some vaccines contain weakened versions of a bacteria or virus, other vaccines contain only part of the bacteria or virus. Some vaccines contain only the genetic material for a specific protein and direct the body to produce a small amount of that protein. The body’s immune system reacts defensively once it detects this protein.

After vaccination, the immune system is prepared to respond quickly and forcefully when the body encounters the real disease-causing organism.

Below is the typical process that FDA expects vaccine developers to follow to generate the information it needs to assess the safety and effectiveness of a vaccine to prevent an infectious disease:

Illustration of the Vaccine Approval Process.  Includes R&D, Pre-Clinical, Phase 1, Phase2, Phase 3, BLA Submitted to FDA, and Phase 4
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