We identified 15 serious games specifically designed for HIV prevention with 4 different genres, as presented in Table 2. There was 1 untitled game. Role-playing was the predominant category of serious games that focused on HIV prevention (n= 6). Among role-playing games, there were 4 educational games, including Play Forward: Elm City, Tumaini, SwaziYolo, and Battle in the Blood [29], and 2 games aiming to reduce risk behaviors, including Socially Optimized Learning in Virtual Environments (SOLVE) and DRAMA-RAMA, the latter of which focused on strengthening peer resistance skills. The second most popular game genre was adventure (n=3), including an educational game called The Secret of Seven Stones (SSS) and an action-oriented adventure game called ViralCombat [30] designed to encourage the use of antiretroviral medications to reduce the risk of acquiring HIV infection. Another game was BattleViro, which encouraged adherence to prescribed antiretroviral treatment (ART). Other genres of serious games among these studies included (1) racing (Fast Car: Travelling Safely around the World, a game that sought to educate adolescents on HIV prevention), (2) a collection of party games (The Test [40], which promoted HIV testing), and (3) an untitled exergame that promoted physical rehabilitation. Another game, My Future Begins Today, which promoted sexual well-being in low-technology settings, had an unidentified genre. [31] Three serious games for cognitive rehabilitation and one collection of games specifically developed to increase adherence to ART also had unidentified genres.

To classify the outcomes of the studies using serious games for HIV intervention and care, we defined 2 types of outcome. The first type was “preliminary results”; these studies focused on proofs of concept for the intervention. Typically, these studies were conducted in a laboratory setting. The second type of outcome was “significant results”; these studies implemented and tested the solution in real-world environments.

In a pilot study, a theory-based smartphone game titled Tumaini [32] was designed to delay the age of a couple having their first sex and to promote condom use in young Kenyans. The preliminary results indicated that participants who played Tumaini for an average of approximately 27 hours showed significant gains in sexual health–related knowledge and self-efficacy, behavioral intentions for risk-avoidance strategies, and sexual risk communication. This pilot study suggests the need for further research to assess the efficacy of game-based interventions. Another study examined the preliminary effects of Insight [34], a computer program that consists of 5 different games designed to improve cognitive and everyday functioning in older adults living with HIV. The study found that those who performed more poorly at baseline on a useful field of view (UFOV) test that measures visual speed of processing and a test of timed instrumental activities of daily living (TIADL) had more training gains in response to the intervention. In addition, the results revealed that a higher HIV viral load and insufficient medication adherence were predictive of greater TIADL training gains. These results illustrate that middle-aged and older adults with HIV who experience problems with speed of cognition and everyday functioning may benefit from this type of training. Another study evaluated the effectiveness and acceptability of a novel game-based training program (ie, an exergame) [35] aiming to improve various aspects of physical frailty in 10 older persons who were living with HIV. The initial results showed a significant reduction in center of mass sway, a significant increase in gait speed during a motor-cognitive assessment, and a remarkable reduction in reported pain. Other studies examined games aimed at enhancing HIV prevention behaviors and adherence to pre-exposure prophylaxis (PrEP). Viral Combat, a novel and entertaining game or app focused on increasing PrEP adherence and imparting HIV prevention knowledge and skills, was first evaluated through qualitative interviews with 20 young men who have sex with men (MSM). Then, a randomized trial with 60 participants preliminarily tested the game’s effectiveness by evaluating knowledge acquisition, behavior change, and skill improvement after the gaming intervention among young MSM.

Although the Viral Combat study is ongoing, it has returned significant data on changes in motivation to increase PrEP adherence and decrease HIV infection. A mobile game called Battle in the Blood was developed as a role-playing game to influence behavior related to the use of HIV services. During a 12-month study period, the game was installed on 3325 unique devices.

The game received a positive response among casual gamers during playtests. The game’s narrative is a key part of its strategy for delivering HIV knowledge. Another project launched a randomized controlled trial (RCT) to examine the initial effects of an action-oriented adventure game called BattleViro [28], which was developed as a tool to improve adherence to ART, decrease viral load, and increase relevant knowledge in 61 youth living with HIV. The study demonstrated promising results but no significant improvements in HIV knowledge, ART knowledge, or social support. However, those who recently started ART (in the past 3 months) and used BattleViro had a greater decrease in viral load, better ART adherence, and more HIV and ART knowledge than the control group.

One game we identified, in the study by Castel et al [27], never started testing as an intervention by the time that the paper was published, as it was still in a participant recruitment stage. Another game, called My Future Begins Today, was developed for sexual health education and was improved based on user responses in a low-technology setting. The 348 participants (193 boys and 155 girls) were students in secondary school aged 11 to 15 years. The results show that groups using a gamified learning approach outperformed those that used a conventional learning approach. Moreover, a game designed for low-technology settings could be more helpful in delivering sexual health education than formal educational approaches.

Other studies have examined mobile health apps and nonvideo serious games that serve as self-learning tools. These include an app called HealthMpowerment (HMP) [36] and an mHealth app [41] to increase users’ knowledge of HIV and social support pertaining to caring for HIV-positive people and living behaviors of HIV-positive people. The contents were evaluated by a group of young MSM and transgender women in the United States and Indonesia. After testing with the target group, the authors determined that the app-based intervention was easily accessible and could support people with HIV in the long term, resulting in a significant increase in comprehension and knowledge of HIV.

We identified 6 serious games with significant results, including PlayForward: Elm City Stories, SOLVE, DRAMA-RAMA (an avatar-based virtual reality game for peer resistance skill building), SSS (a web-based adventure game), and games focusing on cognitive rehabilitation called Captain’s Log and Brain Powered Games.

In a study to evaluate PlayForward [24], a video game that was specifically developed as an HIV prevention tool targeted at HIV risk behaviors (ie, substance use and sex) in young adolescents, the authors showed that after 6 weeks of playing the game, the intervention group had higher knowledge scores than the control group at 6 weeks and at 3 months. Moreover, an analysis of 1,289,903 events in log files of the game revealed that the number of game levels completed was positively correlated with gains in knowledge measured at 6 weeks and at 3 months. These findings demonstrated that PlayForward increased HIV risk–related knowledge among adolescents and that exposure to the video game’s content was highly correlated with knowledge. Another study of the same game [23] analyzed log files from 166 participants in an RCT and showed that higher knowledge scores for substance use at 3- and 6-month follow-ups were related to successfully completing more of the game levels, rather than to total gameplay time.

Another study aimed to investigate the effects of SOLVE [26], a role-playing video game focused on sexual shame reduction among MSM. MSM in the SOLVE intervention reported more shame reduction than MSM in the control condition. Moreover, greater reductions in shame among participants in the SOLVE treatment condition in turn predicted reductions in risky sexual behavior at follow-up. Additionally, SOLVE was the first intervention to significantly reduce shame and risks for MSM from unprotected anal intercourse.

DRAMA-RAMA [37] is an avatar-based video game focusing on peer resistance skill building in teenagers. An RCT was conducted to assess how positively the game was perceived by 45 young Hispanic girls. Separate analyses of covariance showed a significant difference between pre- and posttest scores for peer resistance self-efficacy measured after the game play session, but these findings were not repeated at a 2-month follow-up. The results provided preliminary support for the hypotheses that playing an avatar-based virtual reality technology game would strengthen peer resistance skills and that early adolescent Hispanic girls would have a positive response to this game.

SSS [25] is a web-based adventure game for teenagers aged 11 to 14 years in the United States aimed at education to prevent unwanted pregnancy and sexually transmitted infections. SSS emphasizes educational training to acquire knowledge about sex-related topics and is based on an intervention mapping approach. It can be used at home and is an intergenerational communication channel with parents.

We found 2 studies that examined the efficacy of serious game interventions for cognitive rehabilitation in African children. In the first study, 33 African children with HIV who lived in rural Uganda and were aged between 6 and 12 years played 45-minute sessions of Brain Powered Games several times a week for 2 months. After the intervention, participants demonstrated clinically significant changes on specific Test of Variables of Attention and CogState measures, reflecting processing speed, attention, visual-motor coordination, maze learning, and problem solving. The second study evaluated the neuropsychological and behavioral benefits of Captain’s Log [39], a computer program specially designed for cognitive training and rehabilitation in children living with HIV in Uganda. The 159 participants were randomized to 1 of 3 treatment groups over a 2-month period and were assessed at enrollment, immediately following a 2-month computerized cognitive rehabilitation training (CCRT) course, and 3 months after CCRT completion. The CCRT groups, which used Captain’s Log, had significantly greater gains at the 3-month follow-up compared to a passive control group in an overall mental processing index measured with the Kaufman Assessment Battery for Children, Second Edition (KABC-II); they also showed gains in planning and knowledge. A group that received limited CCRT with the same games rotated randomly from simple to moderate levels of training performed better than a passive control group receiving no training. Moreover, both CCRT arms had significant improvements in CogState Groton maze learning.

In contrast with serious games, gamification is an approach that applies game mechanics in nongame settings. It is used in a broader context and has more specific outcomes. There are typically 3 types of gamification [15]: internal, external, and behavior-change gamification. Internal gamification targets users within an organization, aiming to improve productivity and increase innovation. External gamification is generally driven by marketing objectives to improve relationships between businesses and customers and improves engagement by clients. Finally, the purpose of behavior-change gamification is healthy habit formation among a population. After removing duplicate and conceptual articles describing the initial development phase of gamification projects that lacked a system prototype, we identified 13 different electronic gamified systems in 17 publications. The majority (n=11, 85%) of the surveyed studies used a behavior-change gamification approach and a minority (n=2, 15%) used external gamification. Six mechanics can be distinguished among behavior-change gamification techniques as defined by Werbach and Hunter [15]: challenge, rewards, feedback, resource acquisition, cooperation, and competition. Challenge aims to motivate users to make an effort with content unlocking and requires users’ effort to complete a list of objectives to be fulfilled; rewards are an indicator of players’ achievements; feedback provides information to players about their progress and status during the game through leaderboards or other visual or informational displays; resource acquisition is intended to motivate users to collect and own useful tools; cooperation uses team-building and requires collaboration between players to achieve an objective that is not possible alone; and competition motivates in-game contention between users.

We examined the game mechanics that underlie various game components; these directly affect gamification designs [42], as illustrated in Table 3.

The game components used in the surveyed studies comprised avatars, levels, content unlocking, leaderboards, virtual goods, achievements, badges, points, and teams.

Avatars are visual representations of players in the game. They are presented to learners as their visual representations and future selves. The avatar component of gamification is used to activate the reward mechanic. In the surveyed studies, we found avatar use in gamified systems including Epic Allies, AllyQuest, P3, HMP, Stick To It, Thrive with Me, Bijou [44], Dot [59], and Game Plan.

Levels show the player’s position at any point during the game to serve as feedback. For example, Besoain et al [46] embedded an experience bar, visualized as medals, that was incremented when users had a significant interaction with the system. In Bijou [44], a completion bar was used to give feedback on the level of completion.

Content unlocking allows a player to access game content or narrative without meeting certain points or specific criteria. The component of content unlocking serves the mechanics of challenge, feedback, and reward.

A leaderboard is a list that shows a ranking of players according to their scores and collections after in-game assessment. The leaderboard allows players to monitor their own ranking and compare it with that of others. The leaderboard component is used to initiate competition and feedback mechanics.

Virtual goods are valuable items that players can purchase during the game in exchange for their points. A representative use of virtual goods was in the game Epic Allies, which used “virtual cards” that players can buy and upgrade using points earned by engaging in other parts of the app. This component is used for the resource acquisition mechanic.

Achievements are rights and rewards given to the player in return for accomplishing an objective; they serve the mechanic of rewards. An example is the gems that are used to signify achievements in Bijou [44].

Badges are commonly used for setting goals, providing explanations about learning activities, identifying players who have shared experiences, and providing users with status. For instance, a badge that shows the level of engagement is given to users in UBESAFE [46]

Points are used to measure success and quantify player progress. In the surveyed studies, users earn points if their responses and in-game actions support healthy behavior and are consistent with HIV prevention measures. Players also earn points in a form of in-app virtual currency in the games AllyQuest and P3. Points can also be earned in the form of scores, as in sexual health education programs with a gamification technique [45] and mobile apps. This component serves the mechanics of resource acquisition and feedback.

Teams represent cooperation to achieve common objectives in the game. Participants can recruit team members to achieve in-game challenges in the games Epic Allies and Stick To It. This component serves the mechanic of cooperation.

Additionally, we found that 6 of 7 gamification strategies for health behavior changes determined by behavioral science [43] were discussed in the surveyed articles. The 7 gamification strategies and validated behavior changes were (1) goal setting, (2) increasing capacity to overcome challenges, (3) providing feedback on performance, (4) providing reinforcement, (5) comparing progress, (6) providing social connectivity, and (7) providing fun and playfulness. Only the strategy of providing fun and playfulness was not found to be used in any games. Game mechanics and behavior change strategies that were used in behavior-change gamification in the studies examined here are shown in Table 3.

Moreover, among the surveyed studies, we found one that described a community-based HIV and sexually transmitted infection (STI) testing system [47] that mentioned using gamification techniques, but that article did not clearly explain the game components, game mechanics, or behavior change strategies, except to state that they automated text messages and graphical quizzes. The system appears only to have integrated quizzes into existing systems.

After examination, we found that gamified systems had both educational and advertising purposes using points or scores as the primary element to attract and engage nonpatients who shared similar goals. However, avatar and level elements were commonly used to improve ART adherence in HIV patients.

We found patterns of reward use based on in-game or virtual reward systems [48,50,51] and physical reward systems that allowed exchanging virtual points and in-game currencies into cash prizes or tangible gifts [52-54,56], as illustrated in Table 4.

In addition, there were 3 systems that were classified as using external gamification, that is, social marketing techniques related to a web page’s visitors or use of particular online tools to improve the attitudes of a population toward an HIV testing service and encourage people to physically visit an HIV clinic [60,61] (Table 5).

We identified examples of studies with preliminary outcomes related to the effectiveness of gamified systems that examined the following apps and systems: Stick To It, AllyQuest, Game Plan, a gamified website (HMP), and UBESAFE.

A pilot study assessing Stick To It determined whether an intervention using gamification was acceptable to young MSM in California and effectively increased repeat HIV screening. The preliminary outcome was that engagement in the intervention was moderate; however, the inclusion of game elements was motivating. Additionally, young MSM who enrolled in a clinic were more strongly engaged than young MSM who registered online. Moreover, the repeat HIV screening rate among the subset of participants who were recruited in the clinic was higher than a comparison group of similar young MSM attending the same clinic the previous year. Another pilot study assessed the feasibility and acceptability of AllyQuest [50], a novel smartphone app designed to improve engagement in HIV care and social support among young MSM living with HIV. A pilot trial conducted with 20 participants showed high levels of app use that were positively correlated to HIV self-management outcomes. There was also a statistically significant relationship between the number of days logged into the app and knowledge and confidence in taking HIV medications. These primary outcomes raised the possibility that AllyQuest could impact long-term HIV ART adherence among HIV-positive young MSM. Moreover, a 4-week pilot trial conducted with young Black MSM and transwomen tested HMP [53], a mobile-optimized intervention that included game-based elements to reduce sexual risk behavior by providing information. In this pilot trial, HMP showed promise for being able to deliver a sufficient intervention dose and maintain exposure and engagement over time sufficient to achieve behavioral change. In this qualitative assessment of 15 participants, the researchers found a correlation between the number of times the intervention site was used and stages of behavioral change. Another study explored the initial effectiveness of Game Plan [58], a tablet-based brief motivational intervention for alcohol use and HIV risk. Over 3 months of follow-up, the participants who used Game Plan reported fewer drinking days, fewer binge drinking days, fewer alcohol problems, and fewer new anal sex partners compared to those in the control group. These initial results suggest that web-based brief motivational interventions could be a promising tool to help MSM reduce HIV-related risk behavior. Additionally, a feasibility evaluation of UBESAFE [46] indicated that the gamified features encouraged users to interact more with the system, by up to 100%.

There were 3 studies of gamified systems with significant results (Table 6), including a pedagogical framework called Motivation, Attitude, Knowledge, and Engagement (MAKE), a promotional campaign aimed at STI and HIV prevention called Testing is Healthy, and the gamified website HMP.

An RCT was conducted to investigate the extent to which game-based learning and the gamified MAKE framework [45] could improve sexual health education among 120 young students in Tanzania. The adolescents were divided into groups that received teaching with 1 of 3 methods: game-based learning, gamified MAKE, and the control group, which used a conventional teaching method. The results suggested that the first 2 teaching approaches delivered better learning outcomes than the conventional teaching method and could be used as tools to improve sexual health behavior and increase HIV/AIDS knowledge in young students.

The evaluation of Testing is Healthy [60] used a technology-based platform called Cineplex TimePlay that included gaming elements to engage people who often go to the cinema to answer STI/HIV-related questions. The system also provided a clinic finder service on a website. Although this was the first time this platform was used for sexual health promotion, the campaign received a great response, with 548,410 views and 77,149 plays. Additionally, server-side rendering web analytics showed a significant increase in the clinic finder page’s unique page views between the first and second campaigns. The results demonstrate that this technique could be used to reach a large population at a low cost.

The last study [52] was an RCT that compared the efficacy of the HMP intervention to an information-only control website. The results indicated that the rate of self-reported condomless anal intercourse at 3 months was 32%, suggesting that exposure to an online intervention can reduce the rate of condomless anal intercourse among young Black MSM, at least in the short term.