Community Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Disproportionately Affects the Latinx Population During Shelter-in-Place in San Francisco

Abstract

Background There is urgent need to understand the dynamics and risk factors driving ongoing SARS-CoV-2 transmission during shelter-in-place mandates. Methods We offered SARS-CoV-2 reverse transcription-PCR and antibody (Abbott ARCHITECT IgG) testing, regardless of symptoms, to all residents (≥4 years) and workers in a San Francisco census tract (population: 5,174) at outdoor, community-mobilized events over four days. We estimated SARS-CoV-2 point prevalence (PCR-positive) and cumulative incidence (antibody or PCR-positive) in the census tract and evaluated risk factors for recent (PCR-positive/antibody-negative) versus prior infection (antibody-positive/PCR-negative). SARS-CoV-2 genome recovery and phylogenetics were used to measure viral strain diversity, establish viral lineages present, and estimate number of introductions. Results We tested 3,953 persons: 40% Latinx; 41% White; 9% Asian/Pacific Islander; and 2% Black. Overall, 2.1% (83/3,871) tested PCR-positive: 95% were Latinx and 52% asymptomatic when tested. 1.7% of census tract residents and 6.0% of workers (non-census tract residents) were PCR-positive. Among 2,598 tract residents, estimated point prevalence of PCR-positives was 2.3% (95%CI: 1.2-3.8%): 3.9% (95%CI: 2.0-6.4%) among Latinx vs. 0.2% (95%CI: 0.0-0.4%) among non-Latinx persons. Estimated cumulative incidence among residents was 6.1% (95%CI: 4.0-8.6%). Prior infections were 67% Latinx, 16% White, and 17% other ethnicities. Among recent infections, 96% were Latinx. Risk factors for recent infection were Latinx ethnicity, inability to shelter-in-place and maintain income, frontline service work, unemployment, and household income &$50,000/year. Five SARS-CoV-2 phylogenetic lineages were detected. Conclusion SARS-CoV-2 infections from diverse lineages continued circulating among low-income, Latinx persons unable to work from home and maintain income during San Francisco’s shelter-in-place ordinance.

Evaluation of a novel community-based COVID-19 ‘Test-to-Care’ model for low-income populations

“…The community-based COVID-19 testing campaigns and subsequent test-to-care demonstration project were undertaken in a single, densely populated, highly diverse, U.S. census tract (022901) within the Mission District of San Francisco, California. This represents a 16-square block area with approximately 5,174 residents of whom 58% are Latinx, 34% White/Caucasian, 5% Asian/Pacific Islander, and 1% Black/African American [26]. Many residents live in high density, low-income households; the combined income of 34% of households in the district is less than $50,000 per year.…”

“…In conjunction with our community partners, we designed the T2C Model to provide enhanced, longitudinal clinical and community-based support alongside the SFDPH case and contact investigation services to any participant of the Unidos en Salud Study who tested PCRpositive for SARS-CoV-2 (Fig 1) [26]. In addition to using a community partnership approach, the T2C Model also drew upon our prior experiences and lessons learned from designing and implementing large scale programs to facilitate low-barrier HIV testing and linkage-to-care [30][31][32].…”

“…We undertook a three-week demonstration project of the T2C Model from April 27 th to May 14 th that nested within the Unidos en Salud COVID-19 "Test and Respond" study [26]. The T2C Model was carried out by a bilingual, multidisciplinary team comprised of three full-time CHWs and five part-time healthcare providers.…”

“…Among 3,871 residents and workers tested for COVID-19 from April 25-28, 2020, 83 were PCR-positive (prevalence, 2.1% [95%CI, 1.7-2.7]). We have previously reported the demographics of PCR-positive participants [26], but in brief, positive participants had a median age of 39 years, were predominantly male (76%) and nearly all were Latinx (95%) ( Table 3). Twothirds were frontline service workers and the large majority of participants lived in a household with an annual income <$50,000 ( Table 3).…”

“…We have previously reported on the results of an epidemiologic surveillance study (Unidos en Salud) conducted from April 25-28, 2020 in the Mission Neighborhood of San Francisco California that found that the point prevalence of PCR-positive SARS-CoV-2 infection was 20-times higher among Latinx residents compared to non-Latinx residents (3.9% vs. 0.2%) [26]. Notably, 96% of recent COVID-19 infections were among Latinx individuals who were predominantly low-income, lived in densely populated households and were frontline service workers or unemployed persons who could not afford to shelter-in-place.…”