This C3 project, Community network-driven COVID-19 testing of vulnerable populations in the Central US, will implement and evaluate a COVID-19 testing and vaccination approach that combines an evidence-based Social Network Testing Strategy (SNS) with community developed COVID-19 public health messages (SNS+). C3 will engage two disenfranchised populations across rural and urban sites in states across the Central US (Texas (TX), Louisiana (LA), Arkansas (AR), Indiana (IN), Illinois (IL)). C3 leverages NIDA's Justice Community Opioid Innovation Network (JCOIN), the PIs' extensive community located COVID-19 testing programs, and a network of established community partnerships. The collaborative community-academic partnerships, research and engagement infrastructure, and team's leadership across JCOIN will ensure that C3 can rapidly recruit, enroll and test most disenfranchised community members, (n=2400) and through this process, accelerate any forthcoming COVID-19 public health prevention interventions. C3 focuses on two communities most impacted by COVID-19: 1) Criminal justice involved (CJI) - non-incarcerated people with previous history of arrest/jail/prison, probation/parole, drug-court attendance, witnessed or experienced a negative interaction with police or law enforcement; and 2) Low-income Latinx - community members at 250% or below Federal Poverty Level. Both of these diverse populations, and the overlap between them, have some of the highest rates of COVID-19 infection and death in the United States. Messaging that affirms individual agency and corrects misinformation, combined with accessible and acceptable testing, is required to accelerate COVID-19 prevention for these populations.Using a two-arm randomized controlled trial design, participants will be enrolled into the Social Network testing Strategy (SNS) arm (involves social networking referrals only) or the Social Network testing Strategy with COVID-19 prevention messages (SNS+) messaging arm. The latter includes affirmation/misinformation correction messaging (discussion tools and coaching). SNS and SNS+messaging arms will both include an initial group of index study participants who will refer their network members into the study and the process will repeat itself one more time for a total of 3 waves. Indexes will refer network members (1st degree) and then those network members will refer one more round (2nd degree).

Inclusion criteria:

Index community members will be:

1. 18 years or older (15-28 years old at University of Indiana site);
2. spend majority of their time in the metropolitan area or county where recruited;
3. have access to a phone for 21-day follow-up call; and
4. primary communication in English or Spanish (based on site; Spanish language for Howard Brown/Project Vida and UTSW) AND at least one of the following: (i) ever had CJI (operationalized as any jail, prison, arrest, parole (completed), probation, drug court); (ii) ever had negative interaction with police or law enforcement that did not lead to an arrest or jail/prison time (operationalized as ever stopped, searched, physically or verbally abused, or had another negative interaction with police or law enforcement); (iii) ever witnessed a negative interaction with police or law enforcement (iv) lower-income Latinx (operationalized as at or below 250% of FPL) (Not applicable for University of Indiana).

Social network referrals will be:

1. linked to the index as a "friend, family, coworker or someone you spend time with on a regular basis";
2. visit within two weeks of index visit;
3. 18 years or older;
4. spend the majority of their time in the metropolitan area or county where recruited;
5. have access to a phone for 21-day follow-up call; and
6. primary communication in English or Spanish.

Exclusion Criteria:

1. inability to provide informed consent; and
2. active COVID-19 symptoms per the Centers for Disease Control and Prevention (CDC). Participants with COVID-19 symptoms will be referred for free testing at existing partners for each of the study sites.
3. currently on parole
4. for the University of Indiana site, currently in foster care, on house arrest, on probation, detained at a federal facility or had a police encounter during which the officer(s) either asked for some form of identification and/or issued a traffic ticket, but did not have other CJI involvement.

21 days from initial study visit for each participant