[Conclusions. The precautionary principle: its advantages and risks].

The proposed extension to health of the precautionary principle is the reaction to two social demands: the desire for greater health safety and for more transparency in the decision making process by associating the public. In medical care, all decisions are based on the balance between cost (dangers induced by the treatment) and benefit (the therapeutic effect). It is as dangerous to overestimate the cost, in other words the risks, as it is to underestimate them. The same problem is encountered in public health. If a vaccination is to be prescribed, the beneficial effects must outweigh the risks; however, these risks are inevitable and have been known to exist since the 18th century, but they have been accepted for the public good. It takes courage to make a vaccination mandatory because those who benefit from it will never know, while those who suffer from its ill effects could take legal action. In order to counter accusations, an evaluation must be made beforehand of the risks and benefits, which underlines the important role of expert opinion. Within the framework of the precautionary principle, actions cannot be taken in ignorance and, at the very least, plausible estimations must be made. The analysis of several recent events (contaminated blood, BSE, growth hormone and Creutzfeldt-Jacob disease) shows that the precautionary principle would have had a very limited impact and that only once there was sufficient knowledge was action made possible. The same is true concerning current debates (the possible risks associated with electromagnetic fields, mobile phones and radon); in these three cases, no country in the world has invoked the precautionary principle, but rather the priority has been given to research. The public understands quite readily the cost/benefit relationship. In the case of oral contraceptives, or hormone replacement therapy the public was aware of their possible health risks but judged that the advantages outweighed the risks. The estimation of risks and benefits, the putting into proper perspective the possible risks that can be incurred from any given action, enables the main pitfalls of the precautionary principle to be avoided: the opposition to progress and the refusal of innovation, ever greater bureaucracy, and the waste of funds in the pursuit of an utopian "zero risk". Other drawbacks are more insidious: increased anxiety in the population, the manipulation of opinion by campaigns fomented by commercial or ideological interests, the influencing of practitioners and decision-makers to choose not the best solution but rather the one that will protect them from any future accusations. At the international level, efforts must be made to avoid that the precautionary principle be used for protectionist reasons. Nevertheless, the precautionary principle can have advantages, such as motivating decision-makers in the public or private sector to explain and quantify their reasoning, and to give objective information. However, the medical practitioner should not be tempted to ask that documents be signed as proof of the information given. This example underlines the possible dangers of the strict application of the law in certain cases and the importance of the role of jurisprudence. The precautionary principle will also impose new obligations on the State, which also must conform to the requirements of proportionality between risk and action, transparency and information in the field of care and health. The application of the precautionary principle will require good judgment because the way it is implemented will determine whether its outcome will be for the better or the worse. That is why it is indispensable that jurists, medical practitioners, and scientists work together so that the precautionary principle will be as precisely defined and codified as possible.