UCSF released the final results Thursday from the mass testing of nearly 4,000 people in a Mission District neighborhood, revealing a high proportion of previous infections among low-income, essential Latino workers.
About 6% of the residents tested positive for antibodies in late April and early May, showing they had been previously infected. Around 2% were actively infected at the time. A disproportionate majority of new infections after the shelter-in-place orders were among Latinos who continued to work.
“This suggests health effects of ethnic and socioeconomic inequities in the community increased during San Francisco’s shelter-in-place ordinance and helps explain why (Latino) people have been disproportionately affected by the pandemic,” principal investigator and senior study author Dr. Diane Havlir, chief of the UCSF Division of HIV, Infectious Disease and Global Medicine at San Francisco General Hospital, said in a statement.
Latinos account for half of San Francisco’s coronavirus infections despite representing only 15% of the city’s population. Among residents and workers in the 16-square-block section of the Mission District tested by UCSF, Latinos were more likely to continue to go to work after the shelter-in-place order, which increased their infection rate. Earlier in the pandemic, infections fell along the lines of the racial makeup of the neighborhood – 67% Latino, 16% white, and 17% other. By late April, Latinos accounted for 96% of new infections.
The study cited risk factors including an inability to work from home, unemployment and a household income of less than $50,000 per year.
The percentage of those previously infected – around 6% – was higher than other studies that conducted antibody testing. A community survey by Stanford University in Santa Clara County reported a past infection rate of 2% to 4%, while similar mass testing in the Marin County enclave of Bolinas revealed almost no infections.
The study’s authors and public health experts said the results exemplified the virus’ disproportionate impact on communities of color.
“Pandemics exploit the existing inequities in society, putting a larger health and economic burden on communities who already face structural disadvantages such as income inequality, crowded housing conditions, systemic racism and discrimination,” Dr. Grant Colfax, San Francisco’s director of health, said in a statement.
Mallory Moench is a San Francisco Chronicle staff writer. Email: [email protected] Twitter: @mallorymoench
