Applying vaccinations to the skin might actually be harmful to some individuals, according to Australian researchers.
Because the skin is an essential organ—providing both a barrier for the body’s defense and a source of immunity—this study explored the safety and efficacy of using the skin as a method of immunization compared to using the nose or mouth. Applying bacterial products to the skin as an alternate route of administering immunizations against infectious disease could precipitate autoimmune diseases in those genetically at risk.
In the study, researchers applied cholera toxin to intact mouse skin and found that autoimmune diseases were induced or enhanced in distant organs. However, when the toxin was ingested through the nose or mouth, it was reported to have the opposite effect.
When cholera toxin was applied to the skin alone or in combination with insulin, there was an increase in the rate and onset of type 1 diabetes in genetically susceptible mice.
-Diabetes Care, March 2004