ABSTRACT People with criminal legal system involvement (CLSI) have experienced five times as many COVID-19 infections and have three times the risk of death compared to general population in the U.S. Heavily impacted by COVID-19 and squarely within NIH health disparities populations, people with CLSI are often poor and disproportionately from racial and ethnic minority groups. Despite the increased risk of COVID-19, we expect that only one-half of people with CLSI will get vaccinated. Ongoing COVID-19 testing in communities and among groups that are not vaccinated will be key to containing the pandemic. The messaging that COVID-19 testing will still be important may not be getting through to people who are at risk – a critical driver of disparities. Our team has a unique opportunity to boost testing literacy, access, and uptake using mobile health (mHealth) technologies (text and Web) to reach women with CLSI in community settings who are part of the existing Tri-City Cohort drawn from geographically and socio-politically diverse cities: Birmingham, AL, Kansas City, MO/KS, and Oakland, CA. This application is highly responsive to the RADx-UP Phase II call for research that tests interventions to reduce COVID-19 disparities among underserved populations. Our team is positioned to embed the proposed study into an existing Web-based women’s health literacy intervention platform (www.shewomen.org, 2R01CA181047) for women leaving jail. We are also able to immediately push the mHealth COVID-19 testing literacy intervention to 508 women we have already recruited to a three-city cervical health study of women with CLSI (R01CA226838), and to promptly make this scalable intervention widely available to people with CLSI. We will engage the women as stakeholders to study regional and individual differences in COVID-19 testing and vaccine literacy, access, and uptake. We will use findings to rapidly develop an mHealth intervention focused on COVID-19 literacy, and then push the intervention to CLSI women in the three cities to boost COVID-19 literacy, testing, access, and uptake, and vaccination. Findings will be used to develop dissemination strategies with stakeholders to push the mHealth intervention to the two million women and 11 million men who interface with the criminal legal system annually in the U.S.

RELEVANCE TO PUBLIC HEALTH The primary impact of this study is it will intervene on COVID-19 health disparities among an extremely vulnerable and overlooked population – women with criminal legal system involvement. The intersectional nature of mass incarceration, racism, and COVID-19 have already created profound disparities for an already vulnerable and often overlooked population of women. Once we have developed an easy to use mHealth intervention to boost COVID-19 testing and vaccine literacy, access, and uptake, we will have an open source set of materials and technological platform available to the community of people working directly with people leaving the criminal legal system – a group of two million women who leave jails annually and another 11 million men.