What is a vaccine?

A vaccine is a substance that stimulates the body's immune response; the goal of vaccination is to prevent or control an infection.

How are vaccines developed?

All products selected for use as a potential vaccine go through a rigorous screening process.

To design a preventive vaccine, researchers must start with an idea or strategy. The decision to move forward with human trials is based on pre-clinical results, availability of the product, and the anticipated promise of the approach based on related scientific findings. In addition, before an investigational vaccine can be administered to human subjects in the US, it must first undergo review by the US FDA and Institutional Review Boards at each clinical site.

What types of vaccines are studied in VRC Clinical Trials?

The VRC studies newer types of vaccine concepts for its work on HIV/AIDS, Biodefense and Re-Emerging Infectious Diseases including subunit vaccines, investigational recombinant vector vaccines, and DNA vaccines.

	Subunit Vaccines
	Subunit vaccines, also known as "component" vaccines, contain only individual proteins or peptides from a virus, rather than the whole virus. Instead of collecting protein or peptide components from the virus itself, they are made in the laboratory using genetic engineering techniques.
	Recombinant Vector Vaccines
	Recombinant vector vaccines are based on microorganisms such as viruses or bacteria that have been weakened so as not to cause disease. The viruses or bacteria are used as vectors, or carriers, to deliver genes into the cells of the body. The body produces proteins from the genes and these proteins stimulate an immune response similar to that induced by other types of vaccine or natural infection.
	DNA Vaccines
	DNA vaccines introduce pieces of laboratory-made virus DNA into the body. Unlike recombinant vector vaccines, DNA vaccines do not rely on a viral or bacterial vector. Instead, "naked" DNA containing synthetic viral genes is injected directly into the body. Cells take up this DNA and use it to produce virus proteins. The proteins trigger the body to produce an immune response without a risk of infection from either the virus of interest or a vector.

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