Behavioral interventions reduce self-reported unprotected anal sex among MSM. These results indicate that HIV prevention for this population can work and should be supported. 
Results of previous studies provide a benchmark for expectations in new studies. Meta-analysis can inform future design and implementation in terms of sample size, target populations, settings, goals for process measures, and intervention content.
When effects differ by design variables, which are deliberately selected and planned, awareness of these characteristics may be beneficial to future designs. Researchers designing future small group and individual-level studies should keep in mind that to date, effects of the greatest magnitude have been observed in studies that used count outcomes and a shorter intervention span (up to 1 month).
Among small group and individual-level studies, effects were also greatest when the comparison condition included minimal to no HIV prevention content. Nevertheless, statistically significant favorable effects were also seen when the comparison condition included standard or other HIV prevention content. Researchers choosing the latter option for new studies should plan for larger sample sizes based on the smaller expected net intervention effect noted above.
When effects differ by implementation variables, which become evident as the study is conducted but are not usually selected or planned, caution may be advised so that future studies can reduce bias. Because intervention effects were somewhat stronger (though not statistically significantly so) in studies with a greater attrition in the comparison condition, differential retention may be a threat to validity. Extra effort should be given to retaining participants in comparison conditions.
Among community-level interventions, intervention effects were strongest among studies with random assignment of groups or communities. Therefore the inclusion of studies where assignment of groups or communities was by convenience did not exaggerate the summary effect. The greater effectiveness of interventions including more than 25% non-gay identifying MSM suggests that when they can be reached, these men may be more responsive than gay-identified men to risk reduction efforts. Non-gay identified MSM may have had less exposure to previous prevention messages, so their initial exposure may have a greater impact.
The greater effectiveness of interventions that include efforts to promote personal skills such as keeping condoms available and behavioral self-management indicates that such content merits strong consideration in development and delivery of new interventions for MSM. And the finding that interventions were most effective for majority white populations underscores the critical need for effective interventions for MSM of African and Latino descent.
Further research measuring the incidence of HIV and other STDs is needed. Because most studies were conducted among mostly white men in the US and Europe, more evaluations of interventions are needed for African American and Hispanic MSM as well as MSM in the developing world. More research is also needed to further clarify which behavioral strategies (e.g., reducing unprotected anal sex, having oral sex instead of anal sex, reducing number of partners, avoiding serodiscordant partners, strategic positioning, or reducing anal sex even with condom use) are most effective in reducing transmission among MSM, the messages most effective in promoting these behaviors, and the methods and settings in which these messages can be most effectively delivered.
Evaluation of an HIV risk reduction intervention among African-American homosexual and bisexual men.
To provide the first data which evaluates an HIV risk reduction intervention designed to reduce HIV high-risk sexual behavior in African-American homosexual and bisexual men.
                Participants (n = 318) were recruited from bars, bathhouses, and erotic bookstores, and through homosexual African-American organizations, street out-reach, media advertisements, and personal referrals of individuals aware of the study.
                Participants were randomized into a single or triple session experimental group or a wait-list control group. Both experimental interventions included AIDS risk education, cognitive-behavioral self-management training, assertion training, and attempts to develop self-identity and social support. Data collection involved assessments of self-reported changes in sexual behavior at 12- and 18-month follow-up.
                Participants in the triple session intervention greatly reduced their frequency of unprotected anal intercourse (from 46 to 20%) at the 12-month follow-up evaluation and (from 45% to 20%) at the 18-month follow-up evaluation. However, levels of risky behavior for the control group remained constant (from 26 to 23% and from 24 to 18%) at 12- and 18-month follow-up evaluations, respectively. In addition, levels of risky behavior for the single session intervention decreased only slightly (from 47 to 38% and from 50 to 38%) at the 12- and 18-month follow-up evaluations, respectively.
                Results were interpreted to demonstrate the superiority of a triple session over a single session intervention in reducing risky sexual behavior in this cohort.