With the introduction of highly active antiretroviral therapy (HAART) for HIV in the mid-1990s, the AIDS epidemic entered a less deadly era. Although HAART does not cure HIV infection, it reduces symptoms and complications, delays progression to AIDS, and lengthens life expectancy. As a result, many patients are able to manage their disease as a chronic illness over decades. HAART also dramatically decreases transmission of HIV from mother to child and curtails the spread of the virus among adults.
Unfortunately, despite the advances in treatment and prevention, roughly 50,000 new HIV infections still occur annually in the Nation. A main reason for the epidemic’s stubborn persistence is that an estimated 1 in 5 individuals with HIV do not know they are infected. As a result, they do not receive HAART and are less likely than those who know they are HIV-positive to take precautions to avoid passing the virus to others. Research, in large part supported by NIDA, has produced a strategy to address this circumstance and break the epidemiological impasse: seek out HIV-infected individuals, particularly those in “hard-to-reach” groups that have minimal contact with the health care system; offer them HIV testing and treatment; and provide support to help them stay in treatment.
Route of HIV Transmission Among Adults and Adolescents Injection drug use was involved in 11 percent of diagnosed HIV infections in 2010. Males accounted for 4/5 of all diagnoses. A small number of other routes,** less than 1 percent, are not shown in this chart.* Heterosexual contact with a person known to have, or to be at high risk for, HIV infection
** Includes hemophilia, blood transfusion, perinatal exposure, and risk factor not reported or not identified
Source: Centers for Disease Control and Prevention
NIDA-supported scientists have made decisive contributions to the research basis for the seek-test-treat-retain (STTR) strategy. Dr. Julio Montaner led a study that showed that expanding HAART treatment to cover a larger percentage of HIV-infected individuals in British Columbia, Canada, tamped down the spread of the epidemic throughout the province (“Antiretroviral Treatment Reduces Spread of HIV Among Injection Drug Users”). This study highlighted the importance of applying the STTR strategy to hard-to-reach drug abusers, as most of the reduction in infection rates was attributable to increased HAART coverage of injection drug users.
Research demonstrates unequivocally that drug abusers benefit most from HAART when they also receive treatment for their substance use disorders. Effective therapy enables patients to remain in anti-HIV treatment, adhere to HAART, and better maintain healthy lifestyles that reduce their risk of infecting others. Studies have shown that, for example, HIV-positive opioid injectors who are treated with methadone or buprenorphine adhere to HAART as strictly as HIV-infected patients who do not use drugs. In another study, providing methadone therapy to HIV-positive patients who had been using heroin weekly or more often was associated with a rise in immune system cells. Treatment of stimulant abuse may be particularly important, as cocaine and methamphetamine have been shown to accelerate HIV replication in patients’ blood. Crack cocaine, in particular, reduces HAART effectiveness (“Crack Cocaine Promotes Progression of HIV Infection to AIDS”).
For the past 3 years, NIDA has encouraged research to learn how best to apply STTR to drug-abusing populations both within and beyond the United States. A recent study found that individuals newly presenting at substance abuse treatment programs were more likely to accept HIV testing when it was offered on the spot than when they were referred elsewhere for it. Moreover, acceptance rates were similar with and without comprehensive pre-test HIV counseling. Other studies have focused on individuals in the criminal justice system, men and women who engage in high-risk sexual behavior while intoxicated, injection drug users, and other hard-to-reach, vulnerable groups.
As NIDA funds work to identify and engage HIV-infected individuals in treatment, the Institute is also promoting research to find treatments that can improve on the success of HAART. For example, several Avant-Garde Awards for AIDS Research support novel projects with potential to produce treatment breakthroughs. These include investigations into factors that accelerate and retard viral replication in the blood of infected individuals, mechanisms underlying the virus’ ability to enter and persist indefinitely in tissues that are beyond the reach of current antiretroviral medications, and interactions between the virus and drugs of abuse.
Thirty years since first reports of AIDS in this country, tremendous progress has been achieved. Unfortunately, major obstacles have hindered the extension of these advances to individuals who have both HIV infection and a substance use disorder. Important opportunities for preventing the transmission of HIV have accordingly been missed. Research that focuses on individuals with substance use disorders, the challenges of preventing HIV transmission among them, and the treatment of those who are HIV-positive, is indispensable for containing the HIV epidemic.