Abstinence-plus (comprehensive) interventions promote sexual abstinence as the best means of preventing HIV, but also encourage condom use and other safer-sex practices. Some critics of abstinence-plus programs have suggested that promoting safer sex along with abstinence may undermine abstinence messages or confuse program participants; conversely, others have suggested that promoting abstinence might undermine safer-sex messages. We conducted a systematic review to investigate the effectiveness of abstinence-plus interventions for HIV prevention among any participants in high-income countries as defined by the World Bank.
Methods and Findings
Cochrane Collaboration systematic review methods were used. We included randomized and quasi-randomized controlled trials of abstinence-plus programs for HIV prevention among any participants in any high-income country; trials were included if they reported behavioural or biological outcomes. We searched 30 electronic databases without linguistic or geographical restrictions to February 2007, in addition to contacting experts, hand-searching conference abstracts, and cross-referencing papers. After screening 20,070 abstracts and 325 full published and unpublished papers, we included 39 trials that included approximately 37,724 North American youth. Programs were based in schools (10), community facilities (24), both schools and community facilities (2), health care facilities (2), and family homes (1). Control groups varied. All outcomes were self-reported. Quantitative synthesis was not possible because of heterogeneity across trials in programs and evaluation designs. Results suggested that many abstinence-plus programs can reduce HIV risk as indicated by self-reported sexual behaviours. Of 39 trials, 23 found a protective program effect on at least one sexual behaviour, including abstinence, condom use, and unprotected sex (baseline n = 19,819). No trial found adverse program effects on any behavioural outcome, including incidence of sex, frequency of sex, sexual initiation, or condom use. This suggests that abstinence-plus approaches do not undermine program messages encouraging abstinence, nor do they undermine program messages encouraging safer sex. Findings consistently favoured abstinence-plus programs over controls for HIV knowledge outcomes, suggesting that abstinence-plus programs do not confuse participants. Results for biological outcomes were limited by floor effects. Three trials assessed self-reported diagnosis or treatment of sexually transmitted infection; none found significant effects. Limited evidence from seven evaluations suggested that some abstinence-plus programs can reduce pregnancy incidence. No trial observed an adverse biological program effect.
Many abstinence-plus programs appear to reduce short-term and long-term HIV risk behaviour among youth in high-income countries. Programs did not cause harm. Although generalisability may be somewhat limited to North American adolescents, these findings have critical implications for abstinence-based HIV prevention policies. Suggestions are provided for improving the conduct and reporting of trials of abstinence-plus and other behavioural interventions to prevent HIV.
In their systematic review, Underhill and colleagues found that abstinence-plus programs appear to reduce short-term and long-term HIV risk behavior among youth in high-income countries.
Human immunodeficiency virus (HIV), which causes AIDS, is most often spread through unprotected sex (vaginal, oral, or anal) with an infected partner. Individuals can reduce their risk of becoming infected with HIV by abstaining from sex or delaying first sex, by being faithful to one partner or having few partners, and by always using a male or female condom. Various HIV prevention programs targeted at young people encourage these protective sexual behaviors. Abstinence-only programs (for example, Project Reality in the US) present no sex before marriage as the only means of reducing the risk of catching HIV. Abstinence-plus programs (for example, the UK Apause program) also promote sexual abstinence as the safest behavior choice to prevent HIV infection. However, recognizing that not everyone will remain abstinent, and that in many locations same-sex couples are not permitted to marry, abstinence-plus programs also encourage young people who do become sexually active to use condoms and other safer-sex strategies. Safer-sex programs, a third approach, teach people how to protect themselves from pregnancy and infections and might recommend delaying first sex until they are physically and emotionally ready, but do not promote sexual abstinence over safer-sex strategies such as condom use.
Why Was This Study Done?
There is considerable controversy, particularly in the US, about the relative merits of abstinence-based programs for HIV prevention. Abstinence-only programs, which the US government supports, have been criticized because they provide no information to protect participants who do become sexually active. Critics of abstinence-plus programs contend that teaching young people about safer sex undermines the abstinence message, confuses participants, and may encourage them to become sexually active. Conversely, some people worry that the promotion of abstinence might undermine the safer-sex messages of abstinence-plus programs. Little has been done, however, to look methodically at how these programs change sexual behavior. In this study, the researchers have systematically reviewed studies of abstinence-plus interventions for HIV prevention in high-income countries to get an idea of their effect on sexual behavior.
What Did the Researchers Do and Find?
In an extensive search for existing abstinence-plus studies, the researchers identified 39 trials done in high-income countries that compared the effects on sexual behavior of various abstinence-plus programs with the effects of no intervention or of other interventions designed to prevent HIV infection. All the trials met strict preset criteria (for example, trial participants had to have an unknown or negative HIV status), and all studies meeting the criteria turned out to involve young people in the US, Canada, or the Bahamas, nearly 40,000 participants in total. In 23 of the trials, the abstinence-plus program studied was found to improve at least one self-reported protective sexual behavior (for example, it increased abstinence or condom use) when compared to the other interventions in the trial; none of the trials reported a significant negative effect on any behavioral outcome. Limited evidence from a few trials indicated that some abstinence-plus programs reduced pregnancy rates, providing a biological indicator of program effectiveness. Conversely, there were no indications of adverse biological outcomes such as an increased occurrence of sexually transmitted diseases in any of the trials.
What Do These Findings Mean?
These findings indicate that some abstinence-plus programs reduce HIV risk behavior among young people in North America. Importantly, the findings do not uncover evidence of any abstinence-plus program causing harm. That is, fears that these programs might encourage young people to become sexually active earlier or confuse them about the use of condoms for HIV prevention seem unfounded. These findings may not apply to all abstinence-plus programs in high-income countries, do not include low-income countries, do not specifically address nonheterosexual risk behavior, and are subject to limited reliability in self-reporting of sexual activity by young people. Nonetheless, this analysis provides support for the use of abstinence-plus programs, particularly in light of another systematic review by the same authors (A systematic review of abstinence-only programs for prevention of HIV infection, published in the British Medical Journal), which found that abstinence-only programs did not reduce pregnancy, sexually transmitted diseases, or sexual behaviors that increase HIV risk. Abstinence-plus programs, these findings suggest, represent a reasonable strategy for HIV prevention among young people in high-income countries.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040275.
• US National Institute of Allergy and Infectious Diseases fact sheet on HIV infection and AIDS
• Information from the UK charity AVERT on all aspects of HIV and AIDS, including HIV and AIDS prevention
• US Centers for Disease Control and Prevention fact sheet on HIV/AIDS among young people (in English and Spanish)
• Information on Project Reality, a US abstinence-only program
• Information on Reducing the Risk and on Apause, US and UK abstinence-plus programs, respectively