In spring 2020, as COVID-19 spiked across the country, thousands of East Bay residents signed up for a longitudinal study run by UC Berkeley School of Public Health’s Eva Harris and Lisa Barcellos. The study aimed to better understand the spread of SARS-CoV-2 (the virus that causes COVID-19) in the Bay Area and the effects of social distancing strategies.
Preliminary results show a SARS-CoV-2 positivity rate among participants in July-September 2020 at less than 1%.
Researchers invited more than 300,000 households in 12 East Bay cities to participate in the study. Participants were solicited via postcards and community outreach in English and Spanish. More than 16,000 individuals responded and about 14,500 completed the screening questionnaire.
A random sample of about 7,200 screening respondents were selected to take part in Round 1 of the study and receive in-home testing kits, with an emphasis on individuals who self-identified as a racial or ethnic minority. Of these participants, about 5,500 completed the study questionnaire and about 5,200 returned biospecimen kits including dried blood spots, nasal swabs, and saliva samples. The research team then tested the samples with a sensitive PCR test for the nasal swabs and a commercial total antibody test on the blood samples. Round 1 of the study began in early July and was completed in late September.
“While the test positivity was low across our study region during Round 1, it is important to note that since the end of Round 1 (September), coronavirus cases have surged across the United States,” said Barcellos. “California was doing relatively well, overall, compared to other areas of the country. However, the infection rate is now accelerating, and cases are increasing statewide, including in all nine Bay Area counties. Private gatherings, especially when moved indoors and without masks, seem to be a primary cause. We hope our study participants will continue to follow the CDC guidelines including: 1) Wearing a mask; 2) Washing your hands often (and carry hand sanitizer with you to use if soap and water are not available); 3) Avoiding contact with anyone who is sick; and 4) Maintaining at least 6 feet of distance between yourself and people who don’t live in your household.”
The research team has now embarked on Round 2 of the study, with repeat questionnaires and biospecimen kits being sent to study participants. In total, sampling and data collection will be repeated for a total of three rounds of viral testing and at least four rounds of antibody testing, every 8-10 weeks through mid-2021. The team is seeking additional funding to add more rounds of testing and to continue longitudinal data collection from all study participants to examine health and social outcomes that have resulted from the pandemic and identify genetic as well as behavioral factors that affect risk of infection and/or modify disease manifestation. Importantly, if COVID-19 vaccines become available by mid-2021, the investigators hope to help monitor vaccine uptake and antibody responses to immunization in East Bay communities.