From Ebola to cane toads, biological organisms continue to inflict widespread economic, social and environmental harm. This has resulted in regulatory oversight of potential weeds, pests and pathogens in a broad range of settings such as biosecurity, biocontrol agents, public health, animal and human vaccines, food contaminants, or GMOs. However, regulatory decision making has been hampered by a confusing plethora of approaches and terms used to assess and describe the risks from different types of organism. These difficulties have been compounded by the success of the chemical risk assessment paradigm, which has been widely embraced by the biological community. Nevertheless, microbiologists have long recognised the importance of certain biological/ecological characteristics that differ markedly from consideration of chemicals. In particular, there are two core elements that underpin risk assessment for any type of biological organism. These include: 1) infectivity/invasiveness, which describes the ability of an organism to spread and persist in the environment, and 2) impact, potential harm to a host that can be causally attributed to the presence of the microbe. Both of these elements are shaped by ecological interactions between a potential pathogen, its host, and the environment, including possible vectors. Therefore, risk from microbes should consider the following:

1)      Infectivity/invasiveness

Organism: arrival/entry, establishment/survival, reproduction, dispersal, persistence

Host: susceptibility/resistance of the host to a microbe

2)      Impact

Organism: adverse effects/virulence

Host: sensitivity/tolerance to symptoms

This presentation will describe how these key considerations elaborated by microbiologists and virologists in the 1980s and 1990s can be integrated into a common framework to assess risk across all types of regulatory regimes.