Bolinas COVID-19 Testing Effort Detects No Active Infections

Successful Implementation of State Social Distancing Orders Must be Maintained, Organizers Emphasize

By Elizabeth Fernandez and Nicholas Weiler

Gloved hands performing finger prick blood test
Photo credit: Barbara Ries

A community-led project to provide comprehensive COVID-19 testing to residents, essential workers, and first responders in the town of Bolinas has determined that all of the 1,845 nasal and oral swab tests conducted in the community between April 20 and April 24 were negative for active infection with the novel coronavirus SARS-CoV-2, which causes COVID-19.

UC San Francisco infectious disease specialists and the Marin County Department of Public Health (DPH), who partnered in the testing effort, shared finalized results with the Bolinas community on May 1, 2020.

The results of serological antibody tests — which will reveal whether anyone in the community was previously infected with the virus — are still being analyzed, with results expected in several weeks.

The PCR swab test results do not guarantee that the town is completely free of infection, but do make it unlikely that more than a handful of people, if any, are currently infected, according to UCSF infectious disease researcher Bryan Greenhouse, MD, who led UCSF’s participation in the testing project.

“Zero infections detected in the community mean that everyone’s efforts to adhere to social distancing have been working and that there is very little, if any, active infection. People should feel good about these results, remain confident in the steps they are taking to protect themselves and their community from COVID-19, and continue the safe practices recommended by public health officials,” said Greenhouse, an associate professor in the UCSF Division of HIV, Infectious Disease and Global Medicine, based at Zuckerberg San Francisco General Hospital and Trauma Center, and a Chan Zuckerberg Biohub investigator.

“Our goals were to conduct a safe and meaningful community-wide survey for COVID-19 to better understand coronavirus transmission in a rural community and also to understand how more widespread testing could be accomplished,” said Aenor Sawyer, MD, a UCSF orthopedist and Bolinas resident who served as medical director for the testing program. “We accommodated every Bolinas community member who chose to be tested, including those who are homeless and even those who are homebound. The enrollment was extraordinary, with residents interested in their own status but also very motivated to contribute in some way to ending this epidemic.”

The results reflect well on California’s early adoption of strict stay-at-home orders and Bolinas’s observation of county and state public health mandates in stopping transmission of the disease, project leaders said.

The Bolinas community’s ability to follow California’s shelter-in-place ordinances is aided by the town’s remote, rural location in Marin County, miles from any highway, and its commitment to community members in need. Bolinas has a median annual income of $56,000, below the U.S. average. With 15 percent of residents living below the poverty level, local individuals, businesses and agencies have provided additional support during the pandemic —  including mask and food distribution, rent subsidies, and phone health-checks for high-risk residents — to help all stay healthy.

“We hope that this community testing effort can provide an example of how testing can be expanded to other communities across the state and the nation,” Greenhouse said. “This shows how ‘pop-up’ community testing can be done safely and rapidly, and could be used more systematically to supplement other methods of disease surveillance to inform interventions. This could take many forms – testing representative samples of communities or targeting high-risk populations when and where this information is most needed to determine the effects of interventions and decide on the most appropriate next actions.”

The project to provide comprehensive COVID-19 testing in Bolinas began as a community effort to assess and interrupt the local transmission of COVID-19, and was supported by partnerships with UCSF researchers, county public health officials, local health clinics and a host of volunteers. Analysis of the tests was made possible by the UCSF Clinical Laboratory at China Basin – CZ Biohub, a rapidly developed facility supported by the Chan Zuckerberg Initiative that has enabled UCSF to begin providing COVID-19 test results to public health departments in all 58 California counties.

“We are grateful to Cyrus Harmon and Jyri Engestrom for initiating the project, and to all of our participants and supporters,” added Sawyer, an assistant clinical professor in the UCSF Department of Orthopaedic Surgery. “This effort would not have been possible without UCSF and collaborations with the Bolinas Fire Protection District, Mesa Park, the Bolinas Community Land Trust, the Coastal Health Alliance, Marin County DPH and all the medical workers, translators, funders, and volunteers. These combined efforts will hopefully facilitate further community testing, which has been defined by the medical experts as the way to move safely beyond this phase of the devastating coronavirus pandemic.”

About UCSF: The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. UCSF Health, which serves as UCSF's primary academic medical center, includes top-ranked specialty hospitals and other clinical programs, and has affiliations throughout the Bay Area.