Vaccination and Autoimmune Phenomena

Abstract

The purpose of this review is to provide an up-to-date outlook on autoimmune phenomena associated with vaccination. Autoimmune reactions triggered by vaccination are a rare occurrence, but a frequent cause of concern. Search of available medical literature for terms “vaccination” and “autoimmunity” or “autoimmune” was performed. Additional articles were indentified based on citations in retrieved articles. Initiation of an autoimmune response by vaccination is possible, but rare. Potential mechanisms include molecular mimicry and bystander activation. In addition, adjuvants present in vaccines may trigger an autoimmune response in specifically predisposed persons by stimulating innate immunity. Documented instances of vaccine-related autoimmunity include Guillain-Barre syndrome following 1976 pandemic influenza (New Jersey strain) vaccine, immune thrombocytopenic purpura triggered by measles, mumps and rubella (MMR) vaccine, and myopericarditis associated with smallpox vaccine. Many autoimmune phenomena have been reported to have occurred in individual patients, or series of patients, in temporal association with the administration of a vaccine. However, controlled studies in most such instances either failed to confirm a causal relationship or were not performed. Conclusion – The weight of currently available evidence supports the conclusion that any risks of autoimmune reactions to vaccines are far outweighed by vaccine-afforded protection against infections, particularly in view of the fact that infections, including vaccine-preventable infections, are most important triggers of autoimmunity. However, research into autoimmune reactions apparently initiated by vaccines is potentially of great importance in the continuing quest to improve scientific understanding of how the immune system functions in health and disease, as well as to widen the evidence base for future efforts directed toward additional improvement in vaccine safety.