A Canadian Framework for Applying the Precautionary Principle to Public Health Issues
Weir, Erica, Schabas, Richard, Wilson, Kumanan, Mackie, Chris, Canadian Journal of Public Health
The precautionary principle has influenced environmental and public health policy. It essentially states that complete evidence of a potential risk is not required before action is taken to mitigate the effects of the potential risk. The application of precaution to public health issues is not straightforward and could paradoxically cause harm to the public's health when applied inappropriately. To avoid this, we propose a framework for applying the precautionary principle to potential public health risks. The framework consists of ten guiding questions to help establish whether a proposed application of the precautionary principle on a public health matter is based on adequacy of the evidence of causation, severity of harm and acceptability of the precautionary measures.
Key words: Public health policy; precautionary principle; risk assessment; causation; evidence-based decision making
La traduction du résumé se trouve à la fin de l'article. Can J Public Health 2010;101(5):396-98.
The precautionary principle is one of the central concepts of modern environmental policy. While having many definitions, the principle essentially states that complete evidence of a potential risk is not required before action is taken to mitigate the effects of the potential risk. Incorporated in the Rio Declaration on Environment and Development1 and a founding concept of the Maastricht Treaty2 creating the European Union, the principle has substantially influenced policy concerning risks to the environment. The precautionary principle is also used increasingly in the formulation of public health policy.3 The American Public Health Association has adopted the principle as guidance for formulating policy concerning children's health.4 In Canada, the Krever Commission of Inquiry on the Blood System in Canada5 and the Campbell Commission6 recommend that the precautionary principle guide future responses to impending infectious diseases and other public health threats.
However, the application of precaution to public health is not straightforward. Several issues have emerged in the application of the precautionary principle in the environmental sector. Criticisms include that the unclear definition creates contradictions and loop holes,7 and that the principle blocks technological progress,7 reduces the role of the scientific process in policy-making, and is misused for purposes aside from the protection of health or the environment, such as trade protectionism.
More unique to the field of public health is the risk that the application of precaution to protect the public's health could paradoxically cause harm to the public's health. This could occur through the removal of a potentially beneficial product, for example vaccines or blood products, because of theoretical concerns about harm.8 Indeed one example that resulted in serious public health consequences was the decision not to chlorinate drinking water in Peru because of concerns about the harm of disinfection by-products. This decision contributed to an epidemic of cholera that afflicted more than 500,000 cases and resulted in 4,700 deaths.9 A second example was Zambia's rejection of genetically modified corn during the 2002-2003 famine.10
Despite the problems with applying the principle in public health, the importance of the precautionary principle cannot be ignored. Two Canadian judicial inquiries have called for its use in public health. The lesson from these inquiries is that if the precautionary principle is not defined by Canadian public health officials, others will define it for them.
The purpose of this paper is to provide guidance based on established public health principles and practical experience on how the precautionary principle should be applied. A primary objective is to encourage transparency and accountability in the principle's application.
What is the precautionary principle?
There are multiple interpretations of the precautionary principle ranging from stronger interpretations, which essentially state that persuasive evidence of harm does not have to exist before measures are taken to protect individuals and society from the harm, to weaker interpretations which argue that actions taken to protect against a harm could be taken, but are not required, and the costs of the precautionary measures should be considered. …