HIV/AIDS and Fatalism: Should Prevention Campaigns Disclose the Transmission Rate of HIV?

Among non-specialists, estimates of the HIV transmission rate are generally upwardly biased. This overestimation may be perceived as beneficial because it increases the incentives to have protected sexual relationships. However, a fatalistic reaction may counterbalance this positive effect. Combined with the overestimation of the transmission rate, an occasional unprotected sexual encounter may induce the feeling that ‘the die is cast’, and hence lead to a permanent neglect of condom use. This paper proposes a theoretical model to predict this fatalistic reaction in both regular and casual relationships. Simulations of the model show that the expected transmission rate that would maximise condom use in high-risk populations lies between 0.55 and 8%.