This study systematically reviewed network-based condom promotion interventions. All of the eleven selected network intervention studies found substantial improvement in condom use or biological outcomes when comparing control and intervention conditions. This is the first systematic review focused on social-network based condom promotion interventions among pre-existing social networks. Although the reviewed interventions are not mutually exclusive from community popular opinion leader (CPOL) studies and other peer intervention programs, there are several distinctions that differentiate these social network based condom promotions. Most importantly, these social network interventions all used social networks that were defined by the individuals themselves. The CPOL model chooses leaders of the community, but may not identify the smaller social networks that impact one’s daily interactions. Most of these reviewed studies (10/11) had some measure of intervention effect within the identified network. The network members were either directly involved in the intervention, or indirectly when receiving information from the index participants. Focusing the review on pre-existing social networks allowed us to compare studies that were not post-hoc defined by researchers or others who may be unfamiliar with endogenous social connections. This review demonstrates the benefits and limitations of incorporating pre-existing social networks and relationships when designing condom promotion interventions.
Network-based condom promotion interventions have several advantages that were highlighted in these studies. Ten of the eleven reviewed studies showed substantial improvements in condom outcome measures. The one study that did not find increases in condom use, did find decreases in incident gonorrhea in the intervention group compared to the control. The median time of terminal follow-up was 12 months, substantially greater than 6.3 months found in a systematic review including non-network based condom promotion interventions [26
]. In addition, ten of the 11 studies had retention rates exceeding 80% at the last follow-up visit. The extended follow-up and high retention rate at terminal follow-up visit suggests that groups who are recruited through social network based methods may be easier to follow and retain compared to non-network recruitment methods. Social network based interventions may also be a valuable tool for recruiting marginalized and hard-to-reach populations.
This systematic review also highlighted several limitations both of network based condom promotions and in the assessment of their efficacy. First, social network interventions require the motivation of index participants to recruit network participants as well as disseminate information among their social networks. Additionally, these interventions are methodologically complex, and understanding the social networks before program implementation is crucial. Contamination is a somewhat inevitable research limitation in the studies that used controls, especially in those that studied densely connected social networks. However, while contamination does impact the evaluation of these types of interventions, it does not compromise the potential utility in implementing social network interventions and HIV prevention programs. The reviewed studies only assessed individual outcomes because there are not standardized measures for condom use norms or other group-level determinants of condom use. Several studies have analyzed group norms, but there have been no validated measures focused at this level of analysis [27
This systematic review has several limitations. First, different methods of demonstrating the effect of a social network based intervention were used. While nine studies had a control group, these studies used varying condom outcome measures. Other reviews of condom promotion interventions have noted heterogeneity in outcome measures [26
]. Differential effects of the intervention on casual versus regular partners may have underestimated the net effect of the intervention in the six studies that did not make this differentiation. Second, the reviewed studies had different recruitment methods and differed slightly in the way in which networks were defined and analyzed. Third, measurement of study quality was difficult as there currently is no gold standard for assessing study quality in social network based intervention studies. Finally, although we conducted an extensive search of the literature, some articles that did not focus on condom promotion as a means of HIV/STI prevention may not have been included.
This systematic review demonstrates some areas that are critical for future social network research focused on HIV prevention. More standardized mechanisms for evaluating contamination between intervention and control groups are essential for clearly showing the effect of social network based interventions. Although social relationships between peers and members of risk groups have been studied in greater detail, the local social worlds of brothels and other commercial sex establishments are less clear. Social networks bridging pimps, managers, and other men who control local sex industries may have a strong influence on condom use, either positive or negative. In addition, better understanding networks of men who purchase sex may provide a strong force for organizing condom promotion and related HIV prevention programs [29
] in some regions where such networks exist.
The results of this review highlight the potential utility of social network based intervention programs. Previous network studies of high risk groups have focused on passive disease transmission, but this body of research reveals how high risk social networks can be used to actively promote STI/HIV prevention. The results of the reviewed interventions suggest that the use of network-based approaches lead to increases in condom use and decreases in other HIV-risk behaviors. Further research on how to recruit, retain, and change behaviors among social networks may hold great promise for behavioral STI/HIV prevention.