Vulnerability in practice: Peeling back the layers, avoiding triggers, and preventing cascading effects.

The concept of vulnerability is widely used in bioethics, particularly in research ethics and public health ethics. The traditional approach construes vulnerability as inherent in individuals or the groups to which they belong and views vulnerability as requiring special protections. Florencia Luna and other bioethicists continue to challenge traditional ways of conceptualizing and applying the term. Luna began proposing a layered approach to this concept and recently extended this proposal to offer two new concepts to analyze the concept of vulnerability, namely understanding external conditions that trigger vulnerability and layers of vulnerability with cascading effects. Luna's conception of vulnerability is useful, which we demonstrate by applying her layered view and the new analyses in multiple contexts. We begin by outlining Luna's view and we use vignettes from healthcare involving transgender patients, the care of patients in psychiatric contexts, and research involving prisoners to illustrate how each part of Luna's concept elucidates important moral issues.