New research does not support a belief that children receiving multiple vaccines increase their risk of hospitalization for a nontargeted infectious disease, according to a study in the August 10 issue of JAMA: The Journal of the American Medical Association.
During the last 2 decades, more vaccinations have become available and routine vaccination schedules have become increasingly complex, according to background information in the article. This has led to concern among some that multiple antigen vaccines, such as the measles-mumps-rubella vaccine, or aggregated vaccine exposure could lead to immune dysfunction, resulting in infectious diseases not targeted by vaccination, occurring as a result of an "overload" mechanism. In a 2002 safety review of multiple immunizations and immune dysfunction, the U.S. Institute of Medicine concluded that there was strong evidence for the existence of biological mechanisms by which multiple vaccinations could influence the risk of nontargeted infectious diseases. However, epidemiological and clinical support for the effect has been lacking, and some studies have even favored a beneficial effect on nontargeted infectious diseases.