The Informal Norms of HIV Prevention : The Emergence and Erosion of the Condom Code

This paper develops an economics-based explanation regarding the coordinating role informal norms play in preventing infectious diseases, with particular reference to HIV in the United States. Specifically, it highlights the way in which a set of informal norms, described as “the condom code” by David Chambers (1994), altered the costs and benefits people faced as they engaged in sexual activities that influenced the HIV epidemic. The paper develops some plausible conditions under which the condom code does and does not influence sexual behaviors, which partially resolved problems related to prevention externalities and the collective action problem associated with HIV. In particular, the shared understandings of gay communities across the country established expectations regarding condom use and facilitated the enforcement of such norms. This provides some explanation as to why the condom code was effective during the first decade or so of the epidemic, when the enforcement of such norms was decentralized and relied on social sanctions. With the advent of antiretroviral therapies (ART), pre-exposure prophylaxis (PrEP), and the development of online communities, however, expectations varied, the code has since eroded, and its enforcement more difficult