Reducing Numbers of Sex Partners: Do We Really Need Special Interventions for Sexual Concurrency?

Multiple and overlapping sexual relationships, commonly referred to as sexual concurrency, are often believed to account for the rapid spread of HIV infection. (1–2) Research shows that concurrent sex partners are prevalent in several populations hit hardest by AIDS including gay communities, commercial sex workers, and throughout sub-Saharan Africa. Recent research shows sexual concurrency may be playing a role in resurgent HIV infections among gay and bisexual men in North America (3) and emerging epidemics in Asia.(4) In addition to epidemiological trends, the potential impact of concurrent sex partners on the spread of HIV transmission is biologically grounded. Sexual concurrency is thought to afford the rapid turnover of HIV when multiple partners are exposed to the virus during the brief and highly infectious period of acute infection.(5) Mathematical models suggest that concurrent sex partners during acute HIV infection are a driving force in heterosexually transmitted HIV epidemics of southern Africa. (6–7)

While stimulating great interest, the existing empirical research on the role of sexual concurrency in HIV epidemics is not definitive. In the February 2010 issue of AIDS and Behavior (volume 14, Number 1) Lurie and Rosenthal (2, 8) pointed out that sexual concurrency has not yet been empirically shown to increase HIV transmission beyond what would be expected from multiple sex partnerships that do not overlap in time. They also note that epidemiological evidence is mixed as to whether sexual concurrency is propelling HIV in southern Africa and that there is even evidence that polygamy, certainly an example of concurrency, can protect against HIV transmission. (8–10) At the heart of the controversy surrounding the role of sexual concurrency in HIV epidemics is the question of whether limited HIV prevention resources should be directed at interventions to target sexual concurrency. Furthermore, even if interventions are designed to specifically target sexual concurrency, it is not clear how they would differ from programs that aim to reduce not-necessarily concurrent multiple sex partners.

The jury may be out on whether sexual concurrency is necessary for the rapid spread of HIV, but there is no disputing that multiple sex partners, whether concurrent or serial, are important in HIV epidemics. Recognizing the need for behavioral interventions that reduce numbers of sex partners regardless of their temporal sequencing is not new. Throughout the 1980s and 1990s social marketing campaigns for HIV prevention in US gay communities commonly promoted reducing numbers of sex partners. Indeed, many of the early HIV prevention successes in gay communities and countries like Uganda are attributed to aggressive efforts aimed at reducing numbers of sex partners. (11–12) Because mass public health messages result in behavior change for only a segment of a population, more intensive behavioral interventions have been geared toward reducing numbers of partners.

Several controlled intervention trials have demonstrated significant reductions in numbers of sex partners. Table 1 summarizes the findings from 15 selected prevention trials that report decreased numbers of sex partners over time. All of these studies found evidence for reductions in numbers of sex partners, with eleven trials demonstrating an experimental intervention that reduced numbers of partners to a significantly greater degree than a control condition. The interventions varied in their content and duration, with some lasting several hours and conducted over several sessions while others had only one brief session. All of the interventions included a heavy dose of interactive training for communication and preventive behavioral skills. The interventions were tested in various settings and with a wide range of populations including men who have sex with men, women, substance users, adolescents, and sexually transmitted infection clinic patients. The magnitude of partner reduction varied, with some studies showing more than a three-fold reduction in numbers of sex partners over time.

Table 1.

Partner reduction outcomes from selected behavioral HIV prevention interventions.

Study	Sample	Intervention format	Intervention duration	Partner reduction outcomes
Wenger at al., 1991(13)	STD Clinic Patients, USA	HIV information + HIV testing HIV information	15 min video 10 min counseling	Both groups decreased numbers of partners from baseline to follow up; HIV information 1.7 to 1.3; Information + testing 1.9 to 1.4, with no difference between conditions.
Jemmott et al., 1992(14)	African-American adolescent males, USA	HIV risk reduction counseling Career counseling control	5 hour single session workshop	HIV prevention intervention had fewer partners at the 6 month follow-up.
Mallow et al., 1994(15)	Substance users in recovery, USA	Psychoeducational HIV risk reduction program Information session control	6 hours of small group sessions	HIV risk reduction intervention reduced partners with 75% reporting multiple partners at baseline and 47% at 6 month follow-up.
St. Lawrence et al., 1995 (16)	African-American Adolescents, USA	Behavioral Skills training Educational program control	8 weekly group sessions	Skills training intervention reduced partners 0.7 to 0.3 over 12 months follow-up compared to 0.8 to 0.7 for the Education Program.
Choi, 1996(17)	Self Identified Asian Pacific Islander Gay men, USA	Behavioral skills training workshop Waitlist control	3 hour single session workshop Wait-list control group	Behavioral skills workshop had fewer partners (3.9) at the 3 month follow-up compared to waitlist (6.4).
Kelly et al., 1997 (18)	Psychiatric patients, USA	Cognitive behavioral skills training + advocacy training Cognitive behavioral skills training AIDS education control	7 90 min small group sessions for skills interventions 60 min education	Cognitive behavioral skill training + advocacy training reduced partners over 3 months from 1.7 to 0.9, but cognitive behavioral skills alone did not, from 0.9 to 0.9.
Kamb et al., 1998(19)	STI clinic patients receiving HIV testing	Standard single session risk reduction counseling Standard counseling plus ongoing group intervention Didactic health messages	20 min post HIV test 20 min post HIV test + 3 60 min groups 5 min	Brief standard session reduced number of new and casual partners over the other conditions.
St. Lawrence et al., 2002(20)	Drug-dependent adolescents, USA	Information +skills based safer sex + risk sensitization Health information + safer sex skills-based training Health information control	12 90 min sessions	Baseline to 12m follow up, both skills-based conditions showed greater decrease in number of partners; Information + Skills, reduced from 5.1 to 1.6 partners, the Information + Skills + sensitization from 4.8 to 1.6.
Rotheram-Borus et al., 2003(21)	Runaway adolescents from 4 shelters, USA	Street Smart intervention: HIV knowledge, coping skills, barriers to safe sex, emotional regulation, risk assess Care as usual control group	9 small group sessions	Average number of partners lower for intervention condition at 24 month follow up among females but not for males.
Shain et al., 2004(22)	Women STI clinic patients, USA	HIV prevention small group sessions HIV prevention + monthly support groups Control condition	HIV prevention 3-weekly 3-hour group sessions	HIV Prevention intervention reduced new STI infections and reduced multiple sex partners. Reductions in multiple sex partners explained protection against STI.
Carey et al., 2004(23)	Psychiatric patients, USA	HIV risk reduction Substance abuse reduction Standard of care control	10 small group sessions	Pre-intervention to 6m follow up: HIV 1.25 to 0.97 SUR 1.41 to 0.95 CTR 1.24 to 1.07 HIV risk reduction reduced number of partners from 1.2 to .9, and substance use reduction interventions reduced number of partners from 1.4 to .9; both reductions were greater than standard of care control, from 1.2–1.0.
Jemmott et al., 2005(24)	Latin/African American adolescent females, USA	Skills based counseling Information based counseling Health promotion counseling control	4.5 hour single session workshop	Skills based intervention had greater decrease in partners from baseline to 12m follow up (1.04 to .93) compared to information based and health promotion conditions.
Kalichman et al., 2007(25)	STI clinic patients, South Africa	Motivation/skills HIV and alcohol use risk reduction counseling HIV information control	60 min single counseling session 20 min single counseling session	Motivational/skills condition reduced number of partners from 2.5 to 1.2, with no difference from the control condition
Kalichman et al., 2008 (26)	Men who use alcohol recruited from community venues, South Africa	Alcohol-sex risk reduction skills workshop Alcohol risk education control	Single 3 hour session Single 1-hour session	Reductions in partners occurred in the skills intervention, but moderated by alcohol use; lighter drinkers reduced having 2+ partners from 12% at baseline to 6% at 3-month and 8% at 6-month follow-up
Carey et al., 2009(27)	STD clinic patients, USA	Brief motivational counseling or brief educational session Intensive information groups Intensive motivational and skills groups	15 min 4 hrs 4 hrs	Number of partners reduced from 2.7 to 1.9 over 12-months with no differences between experimental intervention conditions

Examining the outcomes reported within these trials suggests that reducing numbers of sex partners may not be any more difficult to achieve than changing other sexual behaviors, such as increasing condom use. In addition, reductions in sexually transmitted infections (STI) has not been directly linked to partner reductions relative to other changes in behavior. Research is needed to better understand motivations for maintaining multiple sex partners and how the meaning of multiple partners differs by gender, sexual orientation, and culture. The importance of multiple sex partners in facilitating the spread of HIV is indisputable. The importance of acute HIV infection in HIV transmission also applies to multiple partners even if non-overlapping and should therefore remain a focus in HIV prevention. Interventions that have shown promise in reducing numbers of sex partners are available and should be implemented in places with high HIV prevalence and high rates of multiple partners, concurrent or not.