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Vol. LXI, No. 7
April 3, 2009

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Sex, Drugs and Viral Load: Integrating HIV/AIDS Prevention and Treatment

A major challenge in the ongoing battle against HIV/AIDS is preventing those who are already infected from transmitting the virus to others. With advances in treatments for HIV infection and other opportunistic illnesses, more people are living longer and healthier lives with HIV. The downside of this otherwise good news is that the time period for an individual’s ability to infect others is growing and too many HIV-positive individuals erroneously believe that their infectivity diminishes as their viral load decreases during effective therapy. As many as 35 percent of HIV-positive individuals report engaging in high-risk sexual behaviors.

Dr. Seth Kalichman, professor of psychology at the University of Connecticut and a grantee of both NIMH and NIAAA, has spent much of his research career trying to understand the behavioral aspects of AIDS and HIV transmission. His work, along with that of others, has examined HIV transmission risk among HIV-infected individuals. These studies, discussed at a recent OBSSR lecture (archived at, confirm that the period immediately preceding HIV infection is characterized by high rates of risky behavior, signifying the potential for rapid spread of HIV during acute infection—that is, before someone knows he or she is infected. Reduction in risky behavior often is seen immediately following an HIV diagnosis, but the tendency toward safer sexual behavior is not always lasting.

Kalichman has found that an individual’s state of health and beliefs about his or her infectivity are important factors relating to transmission risks. Thus, HIV treatments—and their effects on an individual’s health and sense of well being—directly interface with transmission risks, adherence to treatment, infectivity beliefs and actual infectivity. For example, people who do not adhere to therapy also are more likely to engage in high-risk behaviors. Those who believe they are less infectious because treatment has reduced the viral load in their blood also are more likely to engage in risky behavior. In fact, individuals with a low viral load in the blood may still have a high viral load in semen—thus infectivity is not reduced. Only the combination of treatment adherence, lack of resistance to therapy and absence of sexually transmitted diseases (which influence genital shedding of HIV) can actually reduce blood and semen viral load and therefore reduce infectivity.

Kalichman also notes that chronic periods of asymptomatic HIV infection are generally associated with some degree of reversion to risky behaviors. As people feel better, they take on more risk. His team has looked at CD4 cell counts—which are used in making a formal diagnosis of AIDS—and risk behavior. People with low CD4 counts (i.e., progression to AIDS) engage in fewer sexual and drug-related risk behaviors.

In sum, HIV risk reduction interventions for infected people must be tailored to address the health status, beliefs and psychological challenges individuals face as they progress through the stages of HIV infection. Kalichman is conducting a randomized clinical trial testing individual and group interventions aimed at prompting beliefs and behaviors that contribute to safer sexual behaviors, stress reduction and treatment of depression, substance abuse and isolation—all factors that contribute to behaviors that increase risky behavior and higher rates of HIV transmission. NIHRecord Icon

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