Background
Worldwide, there are more than 13.3 million orphans and vulnerable children affected by Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) (HIV OVC), defined as individuals below the age of 18 who have lost one or both parents to HIV/AIDS or have been made vulnerable by HIV/AIDS; they are at risk for negative psychosocial and cognitive outcomes.

Purpose
This meta-analysis aimed to examine the scientific literature on available interventions for HIV OVC, with a focus on community-based interventions (CBI).

Methods
Systematic electronic searches were conducted from four databases between October 2016 and April 2017 to identify articles investigating the effectiveness of interventions for HIV OVC. Effect sizes were calculated for each article which provided enough information and data points for analyses.

Results
Seventy-four articles were reviewed, including psychosocial interventions (d = 0.30), cognitive interventions (d = 0.14), social protection interventions (d = 0.36), and community-based interventions (CBI; d = 0.36). Study-specific effect sizes varied widely, ranging from −1.09 to 2.26, that is, from a negative effect to an impressively large positive one, but the majority of studies registered small to medium effects (the overall effect size for all studies was 0.32, SE = 0.03, 95% CI: 0.26–0.37). Social protection interventions had the highest positive outcomes whereas CBI tended to have the fewest significant positive outcomes, with some outcomes worsening instead of improving.

Conclusions
Overall, interventions provided to OVC have potential for improving cognitive, psychosocial, and risk-behavior outcomes. Social protection interventions and CBI had the highest effect sizes, but CBI had positive effects on fewer outcomes and demonstrated some negative effects. CBI warrant scrutiny for improvement, as they represent an important form of culturally embedded services with potentially long-term benefits to OVC, yet appear to be differentially effective. Successful components of other types of intervention were identified, including cash grants, mentorship, and family therapy. In addition, more research is needed that attends to which interventions may be more effective for specific populations, or that studies cost-effectiveness.