Adverse reactions to vaccines.

(The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.) Immunization healthcare is becoming increasingly complex as the number and types of vaccines have continued to expand. Like all prescription drugs, vaccines may be associated with adverse events. The majority of these reactions are self-limited and not associated with prolonged disability. The media, Internet and public advocacy groups have focused on potentially serious vaccine-associated adverse events with questions raised about causal linkages to increasing frequencies of diseases such as autism and asthma. Despite a lack of evidence of a causal relationship to a variety of vaccine safety concerns, including extensive reviews by the Institute of Medicine, questions regarding vaccine safety continue to threaten the success of immunization programs. Risk communication arid individual risk assessment is further challenged by the public health success of vaccine programs creating the perception that certain vaccines are no longer necessary or justified because of the rare reaction risk. There is a need for improved understanding of true vaccine contraindications and precautions as well as host factors and disease threat in order to develop a patient specific balanced risk communication intervention. When they occur, vaccine related adverse events must be treated, documented and reported through the VAERS system. The increasing complexity of vaccination health care has led the Center of Disease Control and Prevention (CDC) to identify Vaccine Safety Assessment and Evaluation as a potential new specialty.