COVID-19 Testing in Mission District, Bolinas to Inform Next Steps in Fight Against Disease

Comprehensive Study of Virus’s Spread in Distinctive Bay Area Communities Made Possible by Boosted Statewide Testing Capacity Supported by UCSF Labs

By Nicholas Weiler

lab worker draws blood from person in a car in Bolinas, Calif.

Carlos Medina (foreground), a phlebotomist with Bay Area Phlebotomy and Laboratory Services, is assisted with a patient blood draw by Susanna Lee, a second-year UCSF School of Pharmacy student. Over four days in Bolinas, Calif., researchers are collecting samples using nasal swabs for diagnostic tests of active COVID-19 infection and finger-prick blood samples for antibody testing. Photo by Barbara Ries

UC San Francisco infectious disease researchers and community partners have launched an effort to provide comprehensive, voluntary COVID-19 testing to all residents of two distinctive Bay Area communities – with the goal of informing the fight against the worldwide pandemic by better understanding how the virus has spread under the radar during the nationwide testing shortage.

The study takes advantage of rapidly expanded COVID-19 sample processing capacity at UCSF made possible in partnership with the Chan Zuckerberg Biohub (CZ Biohub) and the Chan Zuckerberg Initiative. Thanks to this increased testing capacity, UCSF recently announced it would offer free test results to county public health departments throughout California, the latest component of the University’s ongoing coordinated response with city, county and state officials to the COVID-19 pandemic.

In the new testing effort, UCSF researchers have partnered closely with community organizations aiming to comprehensively test all residents of a densely populated tract of San Francisco’s Mission District as well as residents of Bolinas, a small, rural town in western Marin County.

For this work, the UCSF team – led by Bryan Greenhouse, MD, Gabriel Chamie, MD, Carina Marquez, MD, and Diane Havlir, MD, all within the UCSF Division of HIV, Infectious Diseases and Global Medicine based at Zuckerberg San Francisco General Hospital and Trauma Center – will build on their collective expertise conducting large, community-based studies of HIV, malaria, and tuberculosis, including in especially vulnerable populations.

The new study aims to counteract the lack of data about the community spread of SARS-CoV-2 that has made the virus so challenging to combat – in part because many people who become infected never show symptoms but can still spread the illness, and many who experience symptoms but recover without hospitalization have never been tested.

“All our public health decisions, including when it will be possible to relax regional and statewide shelter-in-place orders, are driven by rough assumptions about how this virus behaves based on very limited data,” said Greenhouse, an associate professor of medicine at UCSF and a CZ Biohub Investigator. “Studying in detail how the virus has spread in these two distinctive communities will give us crucial data points that we can extrapolate to better predict how to control the virus in similar communities nationwide.”

Standard Nasal Swabs, Antibody Testing for Thousands

At pop-up testing sites located in neighborhood community centers, the researchers will collect samples using nasal swabs for diagnostic tests of active COVID-19 infection, as well as finger-prick blood samples for antibody testing, which can reveal past exposure to the virus in both children and adults. Because diagnostic tests cannot detect the presence of the virus once it is cleared from the body (which can happen whether a person was asymptomatic or recovered on their own), both types of test are essential to understanding how widely the disease has already spread in these communities.

Beginning on April 20, the researchers hope to provide tests over the course of four days for as many as possible of Bolinas’s nearly 2,000 residents, and then, during a four-day testing period beginning on April 25, to the 5,700 residents of a particularly densely populated Mission District census tract.

Study participants who test positive for active COVID-19 infection will get immediate follow-up calls from UCSF infectious disease experts, working hand-in-hand with regional public health departments and community groups, to assist with the process of facilitating isolation and quarantine (for contacts), and to connect persons with active disease to medical support through partnerships with local healthcare networks.

Those who test negative will be expected to continue abiding by shelter-in-place and social-distancing mandates because of the possibility of false negative test results and a general lack of information about the potential for reinfection with the disease.

Partnership Between Community Volunteers, Agencies, Scientists

The idea of community-wide testing for Bolinas residents began as a grassroots effort by locals, who partnered with UCSF researchers, county and state public health departments, and the local Coastal Health Alliance medical provider to ensure the community is fully engaged and supported following testing. The project leaders were inspired by actions of the Italian town of Vo – where community leaders were able to bring the epidemic under control locally through two rounds of comprehensive testing – and hoped something similar could be done in Bolinas.

“This study stands to benefit people at three levels – individuals who will get to learn their disease status, the community for the opportunity to isolate and eradicate the virus, and worldwide through improved ability to understand how this virus spreads,” said Aenor Sawyer, MD, MS, a Bolinas resident and UCSF orthopedic surgeon who has served as project medical director and a liaison between Bolinas community members and university researchers. “This effort has been made possible by extraordinary volunteerism and partnership between the community, local agencies, public health officials, UCSF staff and students, and many others. We hope that this effort can provide a reproducible model for how other communities can build partnerships to provide rapid and comprehensive pop-up testing to their residents, as UCSF begins assisting with testing capability statewide.”

San Francisco’s ongoing response to the pandemic is going to rely on understanding and responding to the penetration of the virus in the Latinx community, said Havlir and colleagues spearheading the Mission District portion of the study.

“The COVID-19 pandemic is disproportionately affecting the Latinx community in San Francisco, both in terms of infection rates and economic hardship, and we have been partnering very closely with the Latino Task Force for COVID-19 to support this community by working to disrupt transmission of the disease,” said Marquez, an assistant professor of medicine at UCSF.

“We’re not only testing but testing and acting,” added Chamie, an associate professor of medicine at UCSF. “Working in partnership with the community and public health officials we are going to make sure everyone gets their results promptly, that people who test positive get the assistance they need to go into isolation and receive medical care, and that thorough contact tracing is conducted to protect everyone in the household.”

Havlir, professor of medicine and chief of the Division of HIV, Infectious Diseases and Global Medicine, emphasized that testing is foundational to every other component of the pandemic response. “In order for us to respond effectively, we need more local community epidemiology like this study to get a sense of where we stand, and where active infection may still be occurring, so as public health officials begin to release constraints on movements we can avoid resurgence of the disease.”

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.