immunization histories as part of their study protocols. The committee is encouraged to see that the Diabetes Autoimmunity Study in the Young (DAISY), which includes cohorts drawn from the general population and from siblings and offspring of persons with IDDM, is already including immunizations as a routinely monitored variable.
Research on the developing human immune system, especially in relation to vaccines, is limited. Studies of animal models are essential to advancing knowledge of the immune system, but those studies have limits because of important differences between humans and animals. Thus, the committee recommends continued research on the development of the human infant immune system. A better understanding of the development of the human immune system is needed as a basis for improved understanding of infants’ response to vaccines and other environmental exposures. In addition, the committee encourages collaborative activities, such as NIAID/NICHD workshops and initiatives, that help the research community synthesize the results of individual research efforts. The inclusion of vaccinologists and vaccine safety researchers in these efforts is encouraged.
Genetic factors are known to be an important source of variability in the responses of the human immune system and in the risks of allergic or autoimmune disease. But understanding of the complex interactions among genetic variables, as well as of the interactions between those variables and environmental exposures (including vaccines and wild-type viral and bacterial agents), remains incomplete. The committee endorses current research efforts aimed at identifying genetic variability in human immune system development and immune system responsiveness as a way to gain a better understanding of genetic susceptibility to vaccine-based adverse events.
For some autoimmune and allergic disorders, surrogate biological markers of disease or disease risk have been identified. In particular, in individuals at risk for type I diabetes, the development of multiple autoantibodies to GAD65 (glutamic acid decarboxylase), IA-2 (protein tyrosine phosphatase-like molecule), and insulin correlate strongly with later development of overt type I diabetes (Notkins and Lernmark, 2001). However, there are to date no other surrogate markers that have sufficient predictive power to be useful in monitoring risk for other autoimmune diseases in children receiving routine immunizations (Leslie et al., 2001). For allergic disorders, the clinical history of allergic diseases should be collected in follow-up evaluations, and the feasibility of specific tests for atopy considered. Studies of the normal development of the immune system in conjunction with surrogate markers of autoimmune and allergic disease and a cohort analysis of autoimmune and allergic disease could be carried out not only in the United States but in infants in a less developed country. Such a compari-