The human immune system has a truly enormous capacity to recognize different proteins and other chemicals called antigens. It can respond to intense and repeated stimulation. The food we eat, the air we breathe, and the water we drink every day is filled with antigens that our immune system recognizes as foreign. Its job is to make appropriate responses to help the body get rid of any foreign substances. The challenge that vaccination presents to the immune system is not likely to be a significant addition to the daily load of foreign antigens entering the body, even for a 2-month-old baby. A study of the effects of repeated immunization with several vaccines was carried out in a group of employees who worked at the United States Army Biological Warfare Research Laboratory in Maryland. The employees had frequently been vaccinated with many routine and experimental vaccines to protect them against the hazards associated with working with dangerous germs. They had also received many skin tests to detect immunity to different germs. Since 1950, the workers had received an average of over 190 injections of 21 different vaccines, and 55 skin tests. These 77 highly immunized workers were compared with 26 workers at the same laboratory who had not received special immunizations or been exposed to laboratory infections. At follow-up intervals of 10, 16 and 25 years, there were no important differences in history, physical examination or laboratory tests. There was no evidence of increased rates of cancer, immune disorders or death in the highly immunized group.

This document was published by the Canadian Paediatric society, 1997.

Posted by the Canadian Paediatric Society, July 1997.

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