On March 11, 2020, the World Health Organization (WHO) officially declared the SARS-CoV-2 (COVID-19) outbreak a pandemic. In Puerto Rico (PR), the first COVID-19 case was confirmed early March 2020. To date, cases have exponentially increased partly due to the lifting of locked-down restriction by the PR government, limited COVID-19 testing, and contact tracing. As a major Public Health Emergency (PHE), the COVID-19 pandemic has disproportionally affected racial and ethnic minorities as well as patients with chronic health conditions. Specifically, residents of PR are socially and epidemiologically vulnerable with one of the highest prevalence rates for chronic diseases (diabetes, hypertension, obesity, HIV) prevalence rates and arbovirus-related diseases, such as Zika and Dengue. Puerto Ricans living on the island are also particularly vulnerable to the current overlapping of the COVID-19 pandemic and natural disasters (earthquake, hurricanes/storms). Limited access to molecular COVID-19 testing throughout PR has been a significant challenge. Without adequate testing, estimates for SARS-CoV-2 (COVID-19) infection rates are limited, and targeted prevention efforts (focused testing) be inadequate. Ponce Research Institute (PRI) with the support of Ponce Health Sciences University (PHSU) - leads the COVID-19 outreach efforts in PR related to earthquake aftershocks, tropical storms, and the COVID-19 pandemic. The PHSU-PRI Research Center for Minority Institutions-Community Engagement Core (RCMI-CEC) leaders in collaboration with community leaders, implemented the COVID-19 prevention education initiative which targets socially vulnerable populations in southern Puerto Rico (the earthquake and aftershocks epicenter). Also, PHSU-PRI epidemiologists (led by Dr. Marzán-Rodríguez, MPI) developed a web-based COVID-19 Epidemiologic Surveillance System (ESSS) in collaboration with the Puerto Rico Public Health Trust (PRPHT, a community partner for this grant) with more than 46,000 surveys completed up to September 2020. The ESSS tool is an online geocoded survey that identifies real-time COVID-19-related symptoms during the last 24 hours; and thus, prioritizes communities for COVID-19 testing. The ESSS tool can be easily accessed on the PRPHT website. Leveraging the current PHSU-PRI COVID-19 prevention efforts and the ESSS infrastructure, the research team proposes a mixed-methods approach for intervention trials for dissecting the impact of an epidemic intelligence (EpI-Net) community-based intervention aimed at increasing COVID-19 testing uptake and prevention practices among socially vulnerable communities in PR. Under Aim 1, the team will train lay community leaders on the use and application of COVID-19 early detection epidemic intelligence tools. Under Aim 2, the team will identify and understand the individual (beliefs and behaviors), social, cultural, and contextual factors facilitating the adoption and adherence to routine COVID-19 testing and prevention practices. Under Aim 3, the team will test EpI-Net intervention preliminary impact on increasing COVID-19 testing uptake and prevention practices among socially vulnerable communities in PR. The working hypothesis is that the integration of lay community leaders, trained in the use of COVID-19 prevention technology tools (EpI-Net), will result in increased COVID-19 testing uptake and prevention practices among the targeted socially and epidemiolocal vulnerable communities in Puerto Rico.