Learn more about vaccines – from how they work to how they’re made – in WHO’s Learn more about vaccines – from how they work to how they’re made – in WHO’s Vaccines Explained seriesVaccines are made up of carefully selected components that work together to protect against disease.
Each vaccine component serves a specific purpose, and each ingredient is tested in the manufacturing process. All ingredients are rigorously tested for safety.
Active components: antigens or their blueprintVaccines contain antigens or the blueprint for making the antigens. An antigen generates an immune response and may be a small part of the disease-causing organism, like a protein or sugar, or it may be the whole organism in a weakened or inactive form.
In place of an antigen, vaccines may also contain genetic material that instructs the body to make specific antigens. Different ways to design a vaccineThere are three main approaches to designing a vaccine.
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