Abstinence-only programs are widespread and well-funded, particularly in the United States and countries supported by the US President's Emergency Plan for AIDS Relief. On the premise that sexual abstinence is the best and only way to prevent HIV, abstinence-only interventions aim to prevent, stop, or decrease sexual activity. These programs differ from abstinence-plus designs: abstinence-plus programs promote safer-sex strategies (e.g., condom use) along with sexual abstinence, but abstinence-only programs do not, and instead often highlight the limitations of condom use. An up-to-date review suggests that abstinence-only programs do not affect HIV risk in low-income countries; this review examined the evidence in high-income countries.
This review included thirteen randomized controlled trials comparing abstinence-only programs to various control groups (e.g., "usual care," no intervention). Although we conducted an extensive international search for trials, all included studies enrolled youth in the US (total baseline enrollment=15,940 participants). Programs were conducted in schools, community centers, and family homes; all were delivered in family units or groups of young people. We could not conduct a meta-analysis because of missing data and variation in program designs. However, findings from the individual trials were remarkably consistent.
Overall, the trials did not indicate that abstinence-only programs can reduce HIV risk as indicated by behavioral outcomes (e.g., unprotected vaginal sex) or biological outcomes (e.g., sexually transmitted infection). Instead, the programs consistently had no effect on participants' incidence of unprotected vaginal sex, frequency of vaginal sex, number of sex partners, sexual initiation, or condom use.
One trial favored an abstinence-only program over usual care for incidence of vaginal sex (n=839), but this was limited to two-month follow-up and was offset by measurement error and six other studies with non-significant effects (n=2615).
One evaluation found several significant adverse (harmful) program effects: abstinence-only program participants were more likely than usual-care controls to report sexually transmitted infections (n=2711), pregnancy (n=1548), and increased frequency of vaginal sex (n=338). These effects were offset by high attrition and other studies showing non-significant effects.
We concluded that abstinence-only programs do not appear to reduce or exacerbate HIV risk among participants in high-income countries, although this evidence might not apply beyond US youth. Trial limitations included underreporting of relevant outcomes, reliance on program participants to report their behaviors accurately, and methodological weaknesses in the trials.