Leveraging Social Networks to Increase COVID-19 Testing Uptake: A Comparison of Credible Messenger and Chain Referral Recruitment Approaches

Until the advent of treatment or a vaccine, our ability to contain COVID-19 must rely on widespread identification of (asymptomatic) positive cases, their subsequent quarantine, and contact tracing of those potentially exposed. Therefore testing efforts must be targeted to those highly vulnerable yet unserved populations, including individuals who use opioids and other substances. These individuals may have poor respiratory or pulmonary health due to substance use (e.g. opioids, methamphetamine), which may make them more susceptible to the virus. Also, these individuals are also more likely to have been incarcerated, or reside on the street, in shelters or in crowded accommodation, further placing them at risk for transmission. We propose research to establish efficacy and sustainability of a community-social network outreach model that partners infectious disease health providers with community based organizations to successfully implement (reach, uptake, delivery and sustainment) COVID-19 point of service, rapid-testing among a highly vulnerable and often underserved population, those who use opioids and other substances. Two distinct social network recruitment strategies with demonstrated efficacy identifying hidden populations and increasing uptake of HIV testing will be adapted and compared. Guided by the EPIS framework, social cognitive theory, and Andersen’s model, this study comprises three phases. Phase 1: Adaptation of outreach recruitment strategies, we will work with our project community advisory board (CAB) to adapt chain-referral and credible messenger strategies for uptake of COVID-19 testing, to finalize recruitment and on-site testing protocols, and to train the CAB in the new protocols and in continuous quality improvement strategies (Aim 1). Phase 2: Strategy Efficacy Trial and Implementation Evaluation, we will compare the two strategies in a cross-over design at two community based organizations (CBOs) with longstanding history of serving hard-to-reach populations in their communities. The comparison of strategies is not to identify the statistical superiority of one sampling strategy in providing population estimates over the other, but instead to identify the ability of each recruit, ment strategy to reach the target population and increase uptake of COVID-19 tests. We will examine the impact of each strategy on (i) reach (recruitment of target population), (ii) COVID-19 testing/repeat testing, and (iii) service delivery (i.e. quarantine, medical care and contact tracing) among those who test positive for COVID-19 (exploratory) (Aim 2). Phase 3: Sustainment, CBOs will implement the strategy proven efficacious based on outcomes, and we will examine their sustainment of the program (Aim 2). Implementation evaluation will identify participant-, staff-, and organizational-level factors that influence the feasibility, acceptability, and sustainability of each strategy in these CBOs. (Aim 3). This investigation will provide much needed information to improve health outcomes and to identify effective system-level responses to prevent or arrest the spread of COVID-19 among the social networks of those who use opioids and other substances, a highly vulnerable and often overlooked population.

在新型冠状病毒肺炎（COVID-19）的治疗方法或疫苗问世之前，我们遏制疫情的能力必须依赖于大范围识别无症状（asymptomatic）阳性感染者、对其实施集中隔离，以及对潜在密切接触者开展接触者追踪（contact tracing）。因此，新冠检测工作需精准聚焦于高脆弱性且服务不足的人群，其中包括阿片类物质（opioids）及其他成瘾物质使用者。此类人群可能因物质滥用（如阿片类药物、甲基苯丙胺（methamphetamine））而存在呼吸系统或肺部健康状况不佳的情况，这会使他们更易感染新冠病毒。此外，这类人群更有可能曾被监禁，或无家可归、居住于庇护所或拥挤的租住环境中，进一步提升了病毒传播风险。
本研究拟构建一套社区-社交网络外展服务模式，以验证其有效性与可持续性：该模式将传染病医疗服务提供者与社区组织（community based organizations, CBOs）建立合作关系，从而在阿片类物质及其他成瘾物质使用者这一高脆弱性且常被忽视的人群中，顺利开展新冠病毒服务点快速检测（point of service rapid-testing）工作，涵盖目标人群触达、检测参与率提升、检测实施及项目维持全流程。
我们将对两种已被证实可有效识别隐蔽人群、提升人类免疫缺陷病毒（HIV）检测参与率的社交网络招募策略进行适配与对比。本研究以EPIS框架（EPIS framework）、社会认知理论（social cognitive theory）及安德森模型（Andersen’s model）为指导，共分为三个阶段。
第一阶段：外展招募策略适配。我们将与项目社区咨询委员会（community advisory board, CAB）合作，针对新冠检测参与率提升需求，适配链式推荐招募（chain-referral）与可信信使招募（credible messenger）两种策略，最终敲定招募与现场检测流程，并针对新流程及持续质量改进策略对社区咨询委员会开展培训（目标1）。
第二阶段：策略有效性试验与实施评估。我们将在两家长期致力于服务本地难以接触人群的社区组织中，采用交叉设计（cross-over design）对两种策略开展对比研究。本研究对比两种策略的核心并非判定某一抽样策略在人群估计上的统计优势，而是探究每种招募策略触达目标人群、提升新冠检测参与率的能力。我们将评估每种策略对以下三方面的影响：(i) 触达率（目标人群招募情况）；(ii) 新冠病毒检测及复检情况；(iii) 新冠病毒检测阳性者的服务供给（即隔离、医疗护理及接触者追踪，此为探索性指标）（目标2）。
第三阶段：项目维持。社区组织将根据试验结果，采用被证实有效的策略推进项目，我们将评估其对该项目的维持情况（目标2）。实施评估将识别影响两种策略在该类社区组织中可行性、可接受性与可持续性的参与者、工作人员及组织层面的因素（目标3）。
本研究将提供亟需的相关信息，以改善健康结局，并为在阿片类物质及其他成瘾物质使用者的社交网络中预防或遏制新冠病毒传播制定有效的系统级应对方案——此类人群属于高脆弱性且常被忽视的群体。