Criminal Prosecution and Human Immunodeficiency Virus–Related Risky Behavior

We examine the consequences of prosecuting people who are human immunodeficiency virus (HIV) positive and expose others to the infection. We show that the effect of such prosecutions on the spread of HIV is a priori ambiguous. The prosecutions deter unsafe sex. However, they also create incentives for having sex with partners who are more promiscuous, which consequently increases the spread of HIV. We test these predictions and find that such prosecutions are associated with a reduction in the number of partners, an increase in safe sex, and an increase in sex with prostitutes. We estimate that doubling the prosecution rate could decrease the total number of new HIV infections by one-third over a 10-year period.