Social network strategy as a promising intervention to better reach key populations for promoting HIV prevention: a systematic review and meta-analysis.

Key populations such as men who have sex with men (MSM), drug users and sex workers are at high risk of HIV infection, but they are marginalised and hidden. Social network strategy (SNS) is purposeful to use social networks to generate social influence, accelerate behaviour change and achieve desirable outcomes among individuals or communities and have been increasingly used for HIV interventions. This study aims to investigate the effects of SNS on HIV prevention among key populations.