SARS-CoV-2 Community Transmission disproportionately affects Latinx population during Shelter-in-Place in San Francisco

Gabriel Chamie, Carina Marquez, Emily Crawford, James Peng, Maya Petersen, Daniel Schwab, Joshua Schwab, Jackie Martinez, Diane Jon Es, Douglas Black, Monica Gandhi, Andrew D. Kerkhoff, Vivek Jain, Francesco Sergi, Jon Jacobo, Susana Rojas, Valerie Tulier-Laiwa, Tracy Gallardo-Brown, Ayesha Appa, Charles Chiu, Mary Rodgers, John Hackett, Amy Kistler, Samantha Hao, Jack Kamm, David Dynerman, Joshua Batson, Bryan Greenhouse, Joe DeRisi, Diane V Havlir, CLIAhub Consortium

Clinical Infectious Diseases
August 21, 2020


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.

Featured Fellows

Maya Petersen

School of Public Health, UC Berkeley
Faculty Affiliate