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Vaccine Safety Testing

 

        Clinical science dictates that in order to determine if immunization or any therapeutic modality is beneficial then the risks must be compared directly to the benefits in an equal manner. The proper scientific endpoint of a clinical trial is the enhancement of health in the treatment group compared to the control group. The strongest clinical endpoint of health is survival however other indicators of health include the number of days in the hospital, number of physician visits, number of days missed from work or school, number of limitations to daily activity , and objectively defined quality of life assessments. Disease specific endpoints such as the prevention of an infection or reduction of a tumor are not proper clinical endpoints since a treatment can prevent an cancer or infectious disease but increase ones risk for even worse diseases.

  

        Adverse reactions to vaccines are greatly under reported (Roden, 1974) because the methods of tracking vaccine side effects are designed to only detect reactions occurring within a few weeks of immunization. Clinical trials performed before vaccines are approved for marketing generally include a small population of healthy children and follow these children less than 3 weeks for adverse reactions. These studies detect events such as fever and seizures. Post marketing surveillance relies not only on physicians to make a temporal connection between immunization and the development of an adverse reactions but to report the association when it occurs. There are however medical legal incentives not to report an adverse vaccine reaction since by reporting the reaction the physician may be implying he or her caused damage to a child.

 

        Reports linking vaccination with autoimmunity and other chronic immune mediated diseases are relatively rare even though vaccination is a common practice and autoimmune diseases are very common diseases. This can be explained by the failure of the physician and or patient to look for autoimmune symptoms follow immunization, recognize that their is a causal relationship between the two conditions, and report the adverse response. Under reporting is a known problem with trying to determine vaccine adverse events (Roden, 1974). Part of the failure to report vaccine induced autoimmunity is because the disease may not occur for many years after vaccination. Cases of autoimmunity induced by rabies vaccines have first become clinically apparent 10 to 20 years after the vaccine was administered (Britton et al., 1978), at a time when the patients have even forgotten that they had received the rabies vaccine. Cases of Guillain-Barre Syndrome have been reported to occur 4-10 months after vaccination (Poser & Behan, 1982) however when autoimmunity occurs more than one month after immunization physicians often fail to recognize the association.

 

        Large clinical trials following 100,000 or more immunized people for over 10 years are necessary to establish safety of immunization. Unfortunately these proper trials have never been performed. Instead the long term effects of vaccines are studied in animals prior to being approved for marketing. Unfortunately these animal toxicity studies are generally done in animals resistant to autoimmunity, diabetes and other chronic immune mediated disorders. Thus the animal toxicity studies offer little reassurance that vaccines are safe.