The Children's Hospital of Philadelphia
Vaccines and Your Baby - How Viruses Work

Kathleen Sullivan, MD: In order to understand how vaccines are made, we must first understand how viruses work. Viruses are constructed kind of like these.

But unlike hard candy, the shell of the virus is made of protein and instead of chocolate, the center of the virus consists of genes. Genes are simply blueprints that tell viruses how to duplicate or reproduce themselves.