HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immunodeficiency syndrome). AIDS, the final stage of the infection process, is characterized by severe immunodeficiency. During this stage, an infected person’s immune system loses its ability to fight off “opportunistic” infections (e.g., pneumonia) that can lead to death.
In the United States, 850,000 people are estimated to be infected with HIV. This estimate is imprecise because not all states require test providers to report HIV to their health departments, and not all infected persons have been tested. Better surveillance data are available for AIDS (because all states do require reporting of AIDS cases), and indicate that 793,026 cases of AIDS have been reported to the Centers for Disease Control and Prevention (CDC) through June 2001. AIDS cases are seen disproportionately among economically disadvantaged persons in urban settings, especially among ethnic and racial minorities. African Americans, in particular, have been especially vulnerable to HIV and account for approximately 40 percent of all AIDS cases in the United States.
Improved antiretroviral treatments for HIV, first developed in 1995, led to a decline in AIDS-related mortality in the United States and other nations with access to modern medicine. However, despite improvements in health among some who are infected with HIV, there is still no cure, and AIDS-related illnesses continue to claim many lives. During 2000, for example, AIDS was the fifth leading cause of death among young adults in the United States.
Global estimates of HIV and AIDS indicate that as many as 40 million people worldwide are now living with HIV or AIDS. The total number of deaths since the beginning of the epidemic is estimated at 22 million. The epidemic does not appear to have slowed, with an estimated 5 million new infections in 2000. Globally, the primary mode of transmission is heterosexual intercourse. Women account for 48 percent of HIV cases worldwide. The majority of people with HIV live in the developing world, with nearly 28.5 million cases on the continent of Africa, 6.1 million cases in south and southeast Asia, and 1.4 million cases in Latin America.
HIV Transmission and Disease Course
HIV transmission occurs when HIV-infected blood, semen, vaginal secretions, or breast milk enters the blood stream of an uninfected person. Once infected, a person experiences an acute illness that may pass unnoticed. Next, there is a extended phase during which the person has few symptoms, but remains infectious to others. After several years, an untreated person may begin to develop symptoms suggestive of HIV disease, such as enlarged lymph glands, fever, weight loss, diarrhea, and fatigue. The immune system has become much less effective, as indicated by reduced CD4 lymphocyte levels; if untreated, infected persons become vulnerable to opportunistic infections, many of which can be life threatening. Treatment of HIV disease can interrupt the natural history of the disease and delay immuno-competence for extended periods.
HIV Antibody Testing
Diagnosis of HIV infection occurs through HIV antibody testing. In the United States it is possible to receive testing at most health departments or through private medical providers. Testing can be anonymous or confidential. Anonymous testing does not require the person seeking testing to provide his or her name. Confidential testing does require the use of a name. The CDC recommends and many states require both pre- and posttest counseling by a trained health professional.
The most commonly used diagnostic test for HIV is the enzyme-linked immunoassay (ELISA) test. This screening test determines whether antibodies to HIV are present in the blood. A positive result does not necessarily mean that the person is infected with HIV because there are other conditions that may lead to a false positive result. For this reason, a positive ELISA test is usually followed by a second ELISA and then by a confirmatory test called the Western blot test. A positive Western blot is generally interpreted as conclusive for an HIV infection. Negative tests do not rule out HIV infection because there is a time interval between HIV infection and the appearance of measurable antibodies (this interval is called the window period). Therefore, if an individual is suspected of being infected with HIV but is thought to be in the window period, testing may need to be repeated at a later date.
Getting tested is important for anyone who believes that she or he may have been exposed to HIV. This allows one to seek medical, psychological, and social services, as appropriate; in addition, testing positive signals the need to avoid behaviors that might inadvertently transmit the virus to others. Although testing is often portrayed as a prevention strategy, it has limited effectiveness for this purpose. Overall, based on a meta-analysis of the scientific literature, HIV counseling and testing tends to lead to risk reduction for those persons who test positive but does not alter risky sexual behavior among those who test negative. However, there have been a number of prevention programs that have been more effective.
Prevention of HIV
Several prevention strategies have been implemented, with varying degrees of success. These strategies target the transmission mode, and are designed to prevent, or at least reduce, the likelihood of the transfer of infected bodily fluids between an infected (HIV+) and an uninfected (HIV—) person.
Efforts to prevent transmission through blood transfusions is the United States have been very successful. Since 1985, all donated blood has been tested for HIV antibodies, and potential blood donors with high-risk histories have been strongly discouraged from donating blood. Outside of the United States, however, many developing countries cannot afford to screen all blood products, and transmission via this mechanism continues. Transmission through blood transfusions and accidental exposures (e.g., occupational needle sticks) are relatively rare in the developed world but continue to occur in the developing world.
Occupational and Accidental Exposures
Accidental and occupational exposures (e.g., needle sticks among health care workers) are rare. Prevention efforts involve the use of “universal precautions,” procedures that begin with the assumption that all patients could be infected with HIV; therefore, emergency medical personnel, health care workers, and others likely to come into contact with bodily fluids are required to protect themselves by wearing latex gloves and other protective coverings when caring for their patients. In addition, health care workers are required to dispose of uncapped needles and syringes in specially made, puncture-resistant containers. Universal precaution procedures also involve the incineration (and careful discarding) of medical waste, trash, and linens in hospitals and other health care settings.
A second strategy to reduce occupational or accidental transmission involves the use of “postexposure prophylaxis” or PEP. This strategy is used only when a person is exposed to an infected bodily fluid. In such cases, the use of PEP reduces the odds of HIV infection occurring by as much as 81 percent. Therefore, the CDC recommends PEP for health care workers who are accidentally exposed to HIV-infected body fluids.
Limited resources in many poorer countries make it difficult for these countries to implement such strategies to reduce accidental and occupational exposures.
Maternal-child transmission can occur through the placenta before birth, during delivery, and through breast feeding. The likelihood of perinatal transmission without medical intervention is estimated to be 25 percent. The risks of such transmission can be reduced to less than 10 percent if a pregnant woman takes zidovudine (AZT) during pregnancy followed by brief treatment of the newborn infant. The risk of transmission through breast feeding is approximately 10 percent. Therefore, in the United States and other developed countries, HIV-infected mothers are discouraged from breast feeding and advised to use commercially prepared formula instead.
However, in countries where clean water is not available and where infectious diseases and malnutrition cause significant infant mortality, the World Health Organization and other organizations recommend breast feeding.
Intravenous Drug Use
Intravenous drug use (IDU) is associated with HIV transmission primarily because drug users often share their drug-injection equipment or “works” with one another. Needles and syringes often have small amounts of HIV-infected blood, which can mix with the next users’ blood and lead to infection. If infected blood is present in a syringe that is shared, the likelihood of transmission is high. In the United States, sharing of unsterilized drug injection needles accounted for 27 percent of the new infections in 2001.
To reduce the risk of HIV infection resulting from IDU, several strategies have been used. One involves exchanging clean needles for used (potentially contaminated) needles. Research completed in the United States has found that HIV incidence was reduced by such needle exchange programs. If needle exchange is not available, then drug users are discouraged from sharing needles with other users and taught how to clean their works prior to use. Perhaps the best strategy is to provide drug abuse treatment. Research reveals that persons who reduce or stop their drug use are less likely to engage in HIV-related risk behavior.
Most cases of HIV in the United States and globally result from sexual transmission. In the United States, unprotected anal and vaginal intercourse are responsible for nearly three-fourths of new infections.
The most effective way to eliminate the sexual transmission of HIV is to abstain from all penetrative sexual activities. Research with adolescents suggests that abstinence programs can have short-term benefits. For example, one study compared the effects of (1) an abstinence-oriented program (2) a safer-sex program, and (3) a health promotion control group implemented with African-American adolescents from middle schools serving low-income, inner-city communities. At the 3-month follow-up, students in the abstinence intervention were less likely to report having had sexual intercourse than were control group participants; however, this effect weakened at the subsequent follow-up evaluations. As expected, students in the safer-sex intervention reported a higher frequency of condom use at all follow-ups. Among adolescents who reported sexual experience at baseline, the safer-sex intervention group reported less sexual intercourse at 6- and 12-month follow-ups than did the control and abstinence intervention groups, and less unprotected intercourse at all follow-ups than did the control group. The results indicate that both abstinence and safer-sex interventions reduced HIV sexual risk behaviors, but that safer-sex interventions have longer lasting effects and are more effective for sexually experienced adolescents.
For adults and adolescents who remain sexually active, prevention efforts tend to encourage “safer sex,” a term which refers to a set of risk reduction strategies, including reducing the number of sexual partners, engaging in a mutually monogamous relationship with an uninfected partner, using condoms consistently and correctly, shifting from higher risk to lower risk sexual activities, and reducing the frequency of unprotected intercourse. These strategies provide different levels of protection against HIV, depending on the circumstances, partner characteristics, and behavioral practices. Most prevention programs tend to emphasize condom use, which provides the best protection for sexually active persons.
There is now a large literature devoted to evaluating the efficacy of a variety of HIV prevention programs. Such programs have been evaluated in a wide range of settings, including clinics that provide services for sexually transmitted disease (STD), family planning, and other sexual health needs; primary, secondary, and higher educational environments; prisons; military facilities; and a range of community-based settings. Programs have been tailored to address the unique needs of men who have sex with men, heterosexual women, adolescents, alcohol and drug users, persons living with mental illness, and other populations.
Two large studies demonstrate that behavioral intervention programs can lead to reduced risk behavior and lowered incidence of new STDs. The National Institute of Mental Health Multisite HIV Prevention Trial Group investigated the efficacy of a group-based intervention with 3,706 high-risk men and women who were recruited from 37 medical clinics across the United States. The intervention evaluated was based on a social-skills-training approach. Patients who received the intervention reported fewer unprotected sexual acts, had higher levels of condom use, and were more likely to use condoms consistently over a 12-month follow-up period. In addition, those men who were recruited from an STD clinic also had a gonorrhea reinfection rate that was one-half that of the control group.
A second study investigated an individualized intervention and was conducted in STD clinics. For this trial, men and women seeking care at such a clinic were randomly assigned to one of three conditions: (1) a four-session counseling program lasting 200 min, (2) a two-session counseling program lasting 40 min, or (3) standard care. Compared with patients receiving standard care, participants in both counseling interventions reported more condom use at 3 and 6 months postintervention. After 6 months, 30 percent fewer participants in both counseling interventions had new STDs, and after 12 months, 20 percent fewer participants had new STDs. Benefits were similar for men and women.
Scholarly reviews of the research literature consistently identify several characteristics of effective HIV prevention programs. First, such programs follow theoretical models that identify multiple determinants of sexual risk behavior. The most prominent models are derived from social cognitive theory and recognize the influence of intrapersonal, interpersonal, dyadic, and other environmental factors. Second, successful interventions usually have a behavioral skills component, which helps program recipients to strengthen self-management, condom use, and interpersonal negotiation skills while becoming better informed about HIV transmission and prevention and more aware of personal vulnerability to HIV infection.
Evaluation of existing prevention programs has also identified some limitations. One concern involves the transfer of research-based interventions to community-based providers. Some transfer is occurring but this tends to happen slowly, and there is concern about whether the adoption of science-based programs is true to the original (tested) intervention. A second concern involves the durability or sustainability of risk reduction. Most research studies follow participants for 1 year or less. Because the need for behavior change is lifelong, research is needed to determine whether the risk reduction benefit persists over longer time intervals.
Living with HIV Disease
Men and women living with HIV disease face numerous challenges, including coping with the stress of a life-threatening illness, adhering to a complex medical regimen, and adopting safer sexual practices.
Coping with HIV Disease
Although the nature and severity of psychological distress resulting from HIV varies from person to person, there is agreement that several phases of the illness are associated with increased anxiety and depressive symptoms. Initial notification of an HIV+ test result, the initial onset of physical symptoms or a sudden decline in CD4 counts, diagnosis of AIDS, and a first hospitalization all represent potent stressors during the course of HIV illness.
Regardless of illness stage, all persons living with HIV must cope with the challenge of living with a chronic, life-threatening disease. Even among those who respond well to treatment, long-term survival is not assured. Sustained viral suppression requires strict adherence to complex drug regimens, and the treatment itself can cause serious and, in some instances, intolerable side effects. Also, because HIV is a stigmatized illness, patients may experience discrimination and rejection from family, friends, partners, and employers. In addition, many HIV-infected individuals must also cope with other life stressors, including social marginalization, unemployment, mental illness, and substance abuse difficulties.
There has been considerable interest in understanding whether psychosocial factors influence HIV disease progression. Studies linking psychosocial variables longitudinally with disease progression in HIV have yielded somewhat contradictory results, but several have provided evidence to suggest that positive psychological adjustment can be associated with improved clinical outcomes. Other investigators have sought to evaluate the impact of stress-reduction interventions on mental health functioning and, in some instances, HIV disease course. For example, cognitive-behavioral stress management programs have shown promise as an approach to reducing psychological distress and improving health-related outcomes among persons living with HIV. This and other studies provide evidence that stress management and supportive interventions can reduce distress and contribute to improved quality of life for people living with HIV.
Adhering to HIV Medications
Successful treatment results in almost total suppression of HIV viral load to “undetectable levels.” However, patients who are unable to take their medications as prescribed are likely to develop drug resistance and may experience poor clinical outcomes. HIV treatment regimens are demanding; they often require patients to take medications throughout the day and night, often at varying intervals. Given the demanding nature of these regimens and the frequent occurrence of unpleasant side effects, it is perhaps not surprising that many patients experience difficulties with taking their medication as prescribed. Studies indicate that suboptimal adherence is reported by between one-third and one-half of patients taking complex HIV treatments.
Research investigating factors that contribute to HIV treatment adherence difficulties point to the challenges of developing interventions to improve adherence. Risk factors that characterize individuals who are at elevated risk for contracting HIV—poverty, social marginalization, substance abuse, and mental illness—are also likely to impair HIV treatment adherence. Psychosocial factors, including social support, psychological distress, and self-efficacy beliefs, also appear to be important factors contributing to combination therapy adherence. Patients report many reasons for missed doses, including simple forgetting, confusion about the treatment regimen, concerns about side effects, and difficulties in fitting complicated pill-taking regimens into a daily routine. Many patients also raise concerns about the psychological impact of being reminded frequently of ones disease and fear that others will find out that they are HIV+. Finally, aspects of the treatment itself, including patients knowledge about treatments, influence adherence.
For example, a recent study found that patients who did not understand the relationship between missed doses and the development of drug resistance were more likely to report poor adherence.
Interventions to promote HIV medication adherence have only recently begun to appear in the scientific literature. Nonetheless, several strategies have emerged, and are often used in practice settings. Initially, many patients benefit from provider-based education regarding the drug regimen and the consequences of poor adherence. Patients need to understand that even slight deviations from prescribed regimens can result in treatment failure. Patients also benefit from having clear expectations regarding medication side effects. Once it is clear that patients understand the importance of taking medications as prescribed, clinicians can then suggest personalized strategies to promote adherence, such as the use of multiple reminders (e.g., daily pill boxes, daily checklists, watch alarms) and the use of problem solving to facilitate integration of pill taking into daily activities. Interventions should also help patients to use social support networks, especially family members and partners, to reinforce patients’ efforts to follow treatment plans.
Adopting Safer Sex Behaviors
Although many persons living with HIV refrain from risky sexual behaviors, studies indicate that at least 30 percent of persons living with HIV engage in risky behaviors. Continued sexual risk behavior among persons living with HIV may inadvertently transmit the virus to uninfected partners, and can lead to more rapid disease progression if such encounters result in coinfections with another STD or “superinfection” with a more virulent HIV strain.
Paradoxically, the availability of improved HIV treatments have eroded commitment to safer sex due to the belief that AIDS is no longer the dire health threat it had been. In a study involving HIV+ and HIV-negative gay men in Chicago, 27 percent of respondents expressed reduced concern about HIV due to new treatments. In addition, reduced HIV concern was strongly associated with unprotected anal sex.
HIV risk-reduction interventions involving persons living with HIV have been quite limited. Research on HIV counseling and testing suggests that posttest counseling promotes short-term reductions in HIV risk behavior among newly infected men and women, but other research reveals that HIV+ persons often revert to high-risk behavior, perhaps due to safer sex fatigue or burnout. Thus, more intensive interventions may be needed to bring about sustained risk reduction and behavior change.
Several studies have investigated such intensive programs, using two different strategies. One strategy focuses on helping HIV+ persons to adjust emotionally and cope with HIV infection. An initial study evaluated a stress management program for HIV-h men that included relaxation training, systematic desensitization, physical exercise, and self-management training. Although risk reduction was not a primary goal of the intervention, participation in the program was associated with a reduction in participants’ number of partners. A second study corroborated the value of an emotion-focused intervention, and reported similar effects using a support group for depressed HIV+ men.
An alternative strategy focuses more directly on sexual risk reduction. Research testing this approach with HIV+ men and women evaluated the benefits of exercises designed to increase disclosure of serostatus to sexual partners and to identify strategies for maintaining safer sex. Compared to participants in a control condition, participants who received this risk reduction intervention reported fewer occasions of unprotected sex at 3- and 6-month follow-up assessments. These studies suggest that interventions that provide emotional support and skills-building exercises can help HIV+ people to reduce risky sexual behavior.
The past two decades have witnessed many advances in the scientific understanding of HIV prevention and care. Health psychologists have played, and will continue to play, an active role in the development, evaluation, and implementation of innovative risk reduction and prevention interventions; they will also continue to help people infected with HIV to adjust to the disease and benefit from new, but increasingly demanding medical treatments. Research gains from this rapidly changing specialty promise continued benefits for our understanding of many other infectious and chronic illnesses.
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