Poxvirus-vectored Vaccines Call for Application of the Precautionary Principle

Genetically engineered viruses (GEVs) used as live vaccines are, and will increasingly become, important for prevention of disease in human as well as animal populations. Poxviruses have a number of attractive theoretical and practical advantages as gene expressing vaccine vectors: their large genomes render construction of multivalent vaccines feasible, the vaccines are easy to produce, the virus particles are very thermostable, and inoculation is followed by long-lasting, protective immune responses. On the other hand, administration and environmental release of GEVs may represent potential unintended harms to human, animal and ecosystem health. We will argue that a strict application of risk-cost/benefit analyses do not cope appropriately with the current lack of scientific understanding and the complexity of ecosystems that will become GEV recipients, and fail to take into account the deeper ethical groundings that shape the scientific and public opinions. To avoid serious, unintended ecological effects of GEVs, it may be necessary to elaborate the ethical basis for protecting health and the environment. The Precautionary Principle (PP) may provide a basis for adequate consideration of ecological and ethical issues of vital importance to protection of health and environment from unforeseen adverse effects of poxvirus-vectored vaccines. To operationalise the PP, we suggest that there is a need to identify and systematise lack of scientific understanding, and to acknowledge uncertainty by initiating research with a broad focus involving interdisciplinary research. In this paper we present three main issues related to the employment of the PP: i) identification of scientific uncertainty and its ethical significance in risk assessment and risk management processes, ii) the need for broad risk assessment as a response to scientific uncertainty, and iii) the need for transparency and public involvement to enhance the debate about normative standards concerning acceptability of benefits, risks and uncertainty with regard to GEV use and release.