Limitations, definitions, principles and methods of risk analysis.

Decisions on veterinary biologicals involve large uncertainties, complexities which cut across many scientific and technical disciplines, and large potential adverse impacts on public health and on important sectors of the economy. How should risk assessment help to guide the decision process on veterinary biologicals? How can risk assessment practices be harmonized internationally, given the different regulatory traditions and institutions of different countries? A broad view of risk assessment is needed, that risk assessment is a framework for summarizing applicable scientific judgement in support of regulatory decision-making. Support for this view of risk assessment is found in the major reports which have defined risk assessment as currently practised by many regulatory agencies in the United States of America (USA). However, some interested and affected parties perceive risk assessment in the USA as overly quantitative and narrowly focused on regulatory standards for carcinogens. An example of risk assessment for microbial contamination indicates how quantitative methods can be used when data are sparse and decisions must be made in the face of great uncertainty. Such quantitative methods can be used to improve communication about risk, to promote consensus in support of controversial decisions, and to identify valuable opportunities for research to reduce the important sources of uncertainty.