Risk Compensation - HIV/AIDS Glossary

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Risk compensation is a theory by which individuals will adjust their behavior based on their perception of risk. It suggests that people who believe themselves to be at lesser risk will take greater chances, even if that assessment is misdirected or ill-informed.

The term was first coined in the 1970s by Sam Peltzman, a professor of economics at the University of Chicago, who wrote in a controversial 1975 article that automobile safety laws did not offset highway deaths due to motorists' belief that they made them inherently "safer." By doing so, Peltzman argued, motorist were far less attentive and took greater driving risks.

While much of his research was later disproved (since motor fatalities actually decreased in the years following publication), Peltzman's theory served as a theoretic template for behavioral research, most recently in the areas of health and communicable disease transmission.

HIV and Risk Compensation

Within the context of HIV/AIDS, risk compensation implies that individuals will sometimes place themselves at greater risk if they believe themselves less vulnerable to either infection or transmission. These perceptions often coincide with the implementation of a biomedical prevention tool, a phenomenon which we have seen in both clinical research and real-world settings, such as with

As an example, while VMMC has shown significant benefit in reducing HIV rates in hyper-prevalent populations, follow-up research has suggested that circumcised men will sometimes engage in high-risk behaviors (e.g., condomless sex, multiple partners) if their perceived risk of infection/transmission is less.

In doing so, a circumcised man can potentially erase the benefits of VMMC and place himself at far greater HIV risk than before the intervention.

In the same vein, individuals who believe themselves "protected" by condoms or TasP can undermine the protective benefit if engaging in sex with multiple partners, for example—particularly if condom use or drug adherence is inconsistent.

Similar concerns have been voiced in recent years by critics of PrEP, who suggested that the once-daily drug regimen—used to prevent infection in HIV-negative people—would encourage condomless sex and, in doing so, increase HIV transmission rates.

Recent research suggests, however, that risk compensation can only undercut the benefit of a preventive tool if it has a low rate of efficacy. Given that PrEP has an extremely high rate of effectiveness (over 90% in certain populations), most agree that the likelihood of such failure is low. On the other hand, when an intervention such as VMMC has an efficacy of between 51% and 60%, the impact of risk compensation can be far greater.

It's important to note, however, that risk compensation does not occur exclusively in the presence of a biomedical prevention. Individuals will often increase risk behaviors with the mere promise of expanded treatment or PrEP, suggesting that such interventions have somehow reduced the impact of HIV within the person’s immediate population.

Remarkably, this association was observed among people who were both HIV-positive and HIV-negative, as well as among those of unknown serostatus.


Cassell, M.; Halperin, D.; Shelton, J.; et al. "Risk compensation: the Achilles heel of innovations in HIV prevention?" British Journal of Medicine. Mar 11, 2006; 332(7541):605-607.

Siegfried, N.; Muller, M.; Deeks, S.; et al. "HIV and male circumcision-a systematic review with assessment of the quality of studies." The Lancet Infectious Diseases. March 2005; 5(3):165-173.

Blumenthal, J. and Haubrich, R. "Risk Compensation in PrEP: An Old Debate Emerges Again." Virtual Mentor. November 1, 2014; 6(11):909-915.

Crepaz, N.; Hart; T; and Marks, G. "Highly active antiretroviral therapy and sexual risk behavior: a meta-analytic review." Journal of the American Medical Association. July 14, 2004; 292(2): 224-e36.

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