At least 5,000 healthy volunteers in the East Bay will soon find out if they have — or ever had — the coronavirus, as UC Berkeley public health researchers begin testing them in early May to learn how far the virus has spread.

The professors from the UC Berkeley School of Public Health and the College of Engineering also want to understand who may be most susceptible to the disease, and to gather information that might help predict the outbreak’s future.

“As the state and federal government look closely at ways for people to return to work and resume their lives, having large, community-based data on asymptomatic individuals will be absolutely essential,” Eva Harris, a UC Berkeley professor of infectious diseases co-leading the study, said in a statement Thursday.

Public health officials say they need to understand how many people have the disease to help contain the outbreak and judge when it’s safe to reopen society.

The researchers will recruit thousands of healthy people ages 18 to 60 from communities across the East Bay through a mail and social media campaign that will go live Monday. Over eight months, the researchers will conduct rounds of diagnostic tests using nasal swabs to identify infections. And they will take saliva and blood samples to look for antibodies, which would indicate that such people had had COVID-19 and recovered — perhaps without ever realizing they’d been infected with the coronavirus. Antibodies develop to fight an infection and remain in the blood for varying lengths of time, depending on the disease. Scientists are still learning about the nature of antibodies to the coronavirus that causes COVID-19.

Volunteers will also fill out questionnaires with personal health and social information.

The federal Centers for Disease Control and Prevention reports that as many as 1 in 4 people infected with the coronavirus don’t show symptoms and could be driving the spread of the disease.

The UC Berkeley researchers said that’s why they created their study. There is a “dearth of data on asymptomatic infections, particularly in potential high-risk areas like the Bay Area, and these data are desperately needed in order to stop transmission,” according to the statement.

Lisa Barcellos, a professor of epidemiology and biostatistics who is co-leading the study, said the research will provide “much-needed insight” into how many people have the disease, how it spreads, and how much the general population is at risk.

UC Berkeley’s long-term study is funded in part by Open Philanthropy, a research and grant-making organization in San Francisco.

Stanford Medicine conducted a similar, short-term study this month with the Santa Clara County Department of Public Health, in which researchers tested the blood of 3,200 people to see whether they had the virus. The results have not yet been released.

Mallory Moench is a San Francisco Chronicle staff writer. Email: mallory.moench@sfchronicle.com Twitter: @mallorymoench