Why are animal products used in the manufacture of vaccines?
Vaccines contain either killed or weakened forms of disease-causing bacteria or viruses, or components of these that stimulate a response by the body’s immune system, which then protects against the development of disease. In the late 19th century, microbiologists began to grow bacteria in the laboratory. The early bacteriologists tried to mimic as closely as possible the environment in an infected person’s tissues by using solutions containing sugars, salts, and various meat extracts to make “growth media.” These kinds of conditions were quite successful in growing bacteria and then viruses in the lab, because these media supplied the many necessary nutrients. Although synthetic media have been developed for growth of many medically important microorganisms, some still require additional nutrients which are easily provided by animal-derived products such as serum and blood. Viral vaccines are produced in living cells, which, similarly, require the addition of complex growth media comp
