When San Francisco implemented its shelter-in place order in mid-March, coronavirus continued to spread through the city’s Hispanic population in parts of the densely populated Mission District, researchers at the University of California, San Francisco reported Thursday.
For the first six weeks the ordinance was in place, the virus continued to spread among the low-income Latino population in a crowded 16-block area of the district, they found.
The team at UCSF worked with the San Francisco Department of Health, the state of California and community organizers on an initiative offering free Covid-19 tests, both nasal swab tests to diagnose active infections and antibody tests to find past infections. They reached almost 4,000 people in the area between April 25-28.
The results: They found that 2% of those given a PCR test – the most accurate type of diagnostic test – were infected with Covid-19 at the time of the test.
Among those who tested positive, infection rates were almost 20 times higher for Hispanic residents than non-Hispanics and 3.5 times higher among immigrant workers than for residents in the district.
Antibody tests indicated 6% of residents had contracted the virus at some point since the beginning of the pandemic, the researchers said in their pre-print report, which has not yet been peer-reviewed.
After comparing the tests, researchers reported, “the vast majority (96%) of new infections were occurring in the Latinx community, whereas those infected earlier in the pandemic were somewhat more representative of the neighborhood as a whole (67% Latinx, 16% white and 17% other).”
Many of those infected could not work from home and could not miss work. Other risk factors for those contracting the virus later, in late April, for example, included frontline service work, unemployment and a household income of less than $50,000 a year.