THIMEROSAL INDUCES TOXIC REACTION IN NONSENSITIZED ANIMALS

The effects of injection of thimerosal solution on nonsensitized anima ls was investigated. Intrafootpad injection of thimerosal solution in nonsensitized mice resulted in a swelling response which peaked 1 h af ter injection and lasted for more than 24 h. Histopathological examina tion showed that there were severe edema and infiltration of polymorph onuclear neutrophils at the site of injection. An increased vascular p ermeability was observed after cutaneous injection of thimerosal solut ion on the back of nonsensitized rats. Since mercuric chloride and met hyl mercury induced severer reactions, and thiosalicylic acid had no e ffect, mercury contained in thimerosal would have caused the reactions observed in this study. These results suggest that part of these hype rsensitivity reactions against thimerosal observed among patients were possibly induced by the toxic effect of thimerosal. Therefore, thimer osal contained as a preservative in vaccine may augment the side-effec ts of the vaccination.