Performance of a Genetic Algorithm for Estimating DeGroot Opinion Diffusion Model Parameters for Health Behavior Interventions

Leveraging social influence is an increasingly common strategy to change population behavior or acceptance of public health policies and interventions; however, assessing the effectiveness of these social network interventions and projecting their performance at scale requires modeling of the opinion diffusion process. We previously developed a genetic algorithm to fit the DeGroot opinion diffusion model in settings with small social networks and limited follow-up of opinion change. Here, we present an assessment of the algorithm performance under the less-than-ideal conditions likely to arise in practical applications. We perform a simulation study to assess the performance of the algorithm in the presence of ordinal (rather than continuous) opinion measurements, network sampling, and model misspecification. We found that the method handles alternate models well, performance depends on the precision of the ordinal scale, and sampling the full network is not necessary to use this method. We also apply insights from the simulation study to investigate notable features of opinion diffusion models for a social network intervention to increase uptake of pre-exposure prophylaxis (PrEP) among Black men who have sex with men (BMSM).

Feasibility study of peer-led and school-based social network Intervention (STASH) to promote adolescent sexual health

Background Effective sex education is the key to good sexual health. Peer-led approaches can augment teacher-delivered sex education, but many fail to capitalise on mechanisms of social influence. We assessed the feasibility of a novel intervention (STASH) in which students (aged 14–16) nominated as influential by their peers were recruited and trained as Peer Supporters (PS). Over a 5–10-week period, they spread positive sexual health messages to friends in their year group, both in-person and via social media, and were supported to do so via weekly trainer-facilitated meetings. The aims of the study were to assess the feasibility of STASH (acceptability, fidelity and reach), to test and refine the programme theory and to establish whether the study met pre-set progression criteria for continuation to larger-scale evaluation. Methods The overall design was a non-randomised feasibility study of the STASH intervention in 6 schools in Scotland. Baseline (n=680) and follow-up questionnaires (approx. 6 months later; n=603) were administered to the intervention year group. The control group (students in year above) completed the follow-up questionnaire only (n=696), 1 year before the intervention group. The PS (n=88) completed a brief web survey about their experience of the role; researchers interviewed participants in key roles (PS (n=20); PS friends (n=22); teachers (n=8); trainers (n=3)) and observed 20 intervention activities. Activity evaluation forms and project monitoring data also contributed information. We performed descriptive quantitative analysis and thematic qualitative analysis. Results The PS role was acceptable; on average across schools >50% of students nominated as influential by their friends, signed up and were trained (n=104). This equated to 13% of the year group. Trained PS rarely dropped out (97% completion rate) and 85% said they liked the role. Fidelity was good (all bar one trainer-led activity carried out; PS were active). The intervention had good reach; PS were reasonably well connected and perceived as ‘a good mix’ and 58% of students reported exposure to STASH. Hypothesised pre-conditions, contextual influences and mechanisms of change for the intervention were largely confirmed. All bar one of the progression criteria was met. Conclusion The weight of evidence supports continuation to full-scale evaluation. Trial registration Current controlled trials ISRCTN97369178

Reinforcement Effects of Social Network Intervention during Nutritional Supplementation in Frail Older Adults

<b><i>Introduction:</i></b> Chronic undernutrition and a homebound state are corelated and are both important components of frailty. However, whether social network intervention combined with protein supplementation is an effective strategy to prevent functional decline among frail older adults is unclear. <b><i>Methods:</i></b> 150 frail older adults participated in a 3-month, 3-armed, community-based clinical trial and were randomly assigned to one of 3 groups: high-protein supplementation (additional 27 g of protein/day), the Social Nutrition Program (additional 27 g of protein/day and social network intervention), or a control group. Those assigned to the Social Nutrition Program group received individual counseling from 1 dietitian and 1 social worker during 6 home visits and were encouraged to participate in 4 sessions of community-based cooking activities, the social kitchen program. Primary outcomes were changes in Physical Functioning (PF) and the Timed Up and Go (TUG) test and were assessed at 0 months (baseline), 1.5 months (interim), and 3, 6, and 9 months (postintervention). <b><i>Results:</i></b> Compared with the control group, participants in the Social Nutrition Program showed an average improvement of 2.2–3.0 s in the TUG test and this improvement persisted for 3 months after the end of the program (post hoc <i>p</i> ≤ 0.030). The Social Nutrition Program also increased PF by 1.3 points while the control group showed a 1.4 point reduction at the end of the program (post hoc <i>p</i> = 0.045). Improvement in PF and TUG results was primarily observed for the socially frail subgroup of older adults in the Social Nutrition Program group rather than the physically frail subgroup. Frequency of leaving home functioned as a mediator (<i>p</i> = 0.042) and explained 31.2% of the total effect of the Social Nutrition Program on PF change. <b><i>Conclusion:</i></b> Our results indicate that social network intervention combined with protein supplementation can improve both the magnitude and duration of functional status among frail older community-dwelling adults.

COVID-19 Contact Tracing Conundrums: Insights From the Front Lines

COVID-19 contact tracing is an induction social network intervention in which the structure of the social network is leveraged to deploy proven COVID-19 interventions such as testing and social distancing. The Howard Brown Health organization has rapidly expanded to include COVID-19 testing, contact tracing, and linkage to resources since the first cases were identified in Chicago, Illinois. COVID-19 is penetrating the most vulnerable networks in the United States; existing inequities are widening as community resources and organizations have had to place services on hold. Here we address several questions that arise as organizations build capacity for contact tracing, including questions involving the potential impact of contact tracing, stakeholders who could be involved, the timing of contact tracing deployment, and the impact potential for digital technology. Contact tracing is critical at later stages of epidemic decline given the potential for isolated outbreaks as larger events, schools, stadiums, and festivals reopen. Local contact tracing efforts can have other indirect benefits with respect to limiting transmission, such as increasing testing rates and addressing structural barriers through provision of life-saving resources and access to crucial social support. (Am J Public Health. Published online ahead of print March 18, 2021: e1–e6. https://doi.org/10.2105/AJPH.2021.306200 )

Disrupting the COVID-19 Misinfodemic With Network Interventions: Network Solutions for Network Problems

Amid the COVID-19 global pandemic, a highly troublesome influx of viral misinformation threatens to exacerbate the crisis through its deleterious effects on public health outcomes and health behavior decisions. This “misinfodemic” has ignited a surge of ongoing research aimed at characterizing its content, identifying its sources, and documenting its effects. Noticeably absent as of yet is a cogent strategy to disrupt misinformation. We start with the premise that the diffusion and persistence of COVID-19 misinformation are networked phenomena that require network interventions. To this end, we propose five classes of social network intervention to provide a roadmap of opportunities for disrupting misinformation dynamics during a global health crisis. Collectively, these strategies identify five distinct yet interdependent features of information environments that present viable opportunities for interventions.

Promoting water consumption among Dutch children: an evaluation of the social network intervention Share H2O

Background There is a need to develop and improve interventions promoting healthy drinking behaviors among children. A promising method could be to stimulate peer influence within children’s social networks. In the Share H2O social network intervention (SNI), peer influence was utilized by selecting a subset of influential children and training them as ‘influence agents’ to promote water consumption—as an alternative to SSBs. Previous research has mainly focused on the process of selecting influence agents. However, the process of motivating influence agents to promote the behavior has hardly received any research attention. Therefore, in the SNI Share H2O SNI, this motivation process was emphasized and grounded in the self-determination theory (SDT). This study evaluated the implementation of the Share H2O SNI, focusing on whether and how applying SDT-based techniques can motivate the influence agents and, indirectly, their peers. Methods This study included data collected in the Netherlands from both the influence agents (n = 37) and the peers (n = 112) in the classroom networks of the influence agents. Self-reported measurements assessed the influence agents’ enjoyment of the training, duration and perceived autonomy support during the training, and changes in their intrinsic motivation and water consumption before and after the start of the intervention. Changes in the peers’ intrinsic motivation, perceived social support, and social norms were measured before and after the start of the intervention. Results The influence agents enjoyed the training, the duration was adequate, and perceived it as autonomy supportive. There was an increase in the influence agents’ intrinsic motivation to drink water and their actual water consumption. Providing personal meaningful rationales seemed to have motivated the influence agents. The intrinsic motivation and perceived descriptive norm of the peers remained stable. The peers reported an increase in their perceived social support and injunctive norm concerning water drinking after the intervention. Influence agents appeared to mainly use face-to-face strategies, such as modeling, talking to peers, and providing social support to promote the behavior. Conclusions The current findings provided preliminary evidence of the promising effects of using SDT-based techniques in an SNI to motivate the influence agents and, indirectly, their peers. Trial registration NTR, NL6905, Registered 9 January 2018, https://www.trialregister.nl/trial/6905

Promoting water consumption among children: a three-arm cluster randomised controlled trial testing a social network intervention

Objective: To test the effectiveness of a social network intervention (SNI) to improve children’s healthy drinking behaviours. Design: A three-arm cluster randomised control trial design was used. In the SNI, a subset of children were selected and trained as ‘influence agents’ to promote water consumption–as an alternative to sugar-sweetened beverages (SSB)–among their peers. In the active control condition, all children were simultaneously exposed to the benefits of water consumption. The control condition received no intervention. Setting: Eleven schools in the Netherlands. Participants: Four hundred and fifty-one children (Mage = 10·74, SDage = 0·97; 50·8 % girls). Results: Structural path models showed that children exposed to the SNI consumed 0·20 less SSB per day compared to those in the control condition (β = 0·25, P = 0·035). There was a trend showing that children exposed to the SNI consumed 0·17 less SSB per day than those in the active control condition (β = 0·20, P = 0·061). No differences were found between conditions for water consumption. However, the moderation effects of descriptive norms (β = –0·12, P = 0·028) and injunctive norms (β = 0·11–0·14, both P = 0·050) indicated that norms are more strongly linked to water consumption in the SNI condition compared to the active control and control conditions. Conclusions: These findings suggest that a SNI promoting healthy drinking behaviours may prevent children from consuming more SSB. Moreover, for water consumption, the prevailing social norms in the context play an important role in mitigating the effectiveness of the SNI.