[3] A Santa Clara County resident (with no foreign travel history) was the earliest known death caused by COVID-19 in the United States, on February 6,[4] suggesting that community spread of COVID-19 had been occurring long before any actual documented case.

This article covers the 13 members of ABAHO, which includes the nine-county Bay Area plus the counties of Monterey, San Benito, and Santa Cruz.

[2][7] Closures due to the pandemic have resulted in mass unemployment and significant disruptions to the economy, replacing local governments' budget surpluses with historic deficits.

Despite strong economic, cultural, and travel ties between California and China, the Bay Area's hospitalization rate and death toll have stayed below initial projections and have compared favorably to East Coast cities.

Researchers have hypothesized that the pandemic's initial impact was blunted by relatively early social distancing measures along with a variety of other factors, including lower population density, a strong car culture and low public transportation ridership, favorable weather in February, and even a loss by the San Francisco 49ers at Super Bowl LIV, discouraging celebrations.

[20][21] Filipino Americans in the Bay Area have also been disproportionately affected by COVID-19 infections, and make up the majority of cases in San Mateo County, California.

[27] The number of confirmed cases is believed to fall significantly short of actual infection rates due to limited testing capacity throughout the pandemic.

Based on serology tests in early April, a revised preprint study from Stanford University estimated that Santa Clara County up to 54,000 residents, or 2.8% of the population, had been infected, compared to the 1,000 confirmed cases at the time.

[1] On January 31, 2020, the Centers for Disease Control and Prevention (CDC) announced the first confirmed case of COVID-19 in the Bay Area and the seventh in the United States, a man in Santa Clara County who had recently traveled to Wuhan.

A February 7 autopsy[39] was completed in April (after virus tests on tissue samples) and attributed the death to transmural myocardial ischemia (infarction) with a minor component of myocarditis due to COVID-19 infection.

The CDC initially refused since the person, who had no known exposure to the virus through travel or close contact with a known infected individual, did not meet the criteria for testing.

[48] After this first case of community transmission in the U.S.,[49] the CDC revised its criteria for testing patients for SARS-CoV-2 and, on February 28, began sending out the new guidelines for healthcare workers.

[118] The Innovative Genomics Institute at the University of California, Berkeley, headed by Dr. Jennifer Doudna converted the genomic-editing research laboratory to run COVID-19 tests.

Despite a widespread need for COVID testing, doctors and hospitals were hesitant to use the newly set up labs in favor of major commercial laboratories like LabCorp and Quest.

[119] As in other parts of California and the United States, the Bay Area has experienced a dramatic increase in unemployment as a result of voluntary and mandatory social distancing measures.

[127] Some major Bay Area manufacturers, such as Lockheed Martin in Sunnyvale and Chevron Corporation in San Ramon, have been exempted from shelter-in-place orders as essential businesses.

[134] Due to the pandemic, the Pleasanton-based Specialty's bakery-café chain, which specialized in corporate catering, permanently closed its more than 50 locations on May 19, 2020, after 33 years in business.

[150] San Francisco's economy is heavily dependent on tourism, which normally employs 90,000 people and generates more tax revenue than any other industry in the city.

[192] By the beginning of April, foot traffic at SFO, SJC, and Oakland International Airport had fallen by 73% compared to before the pandemic, according to Foursquare location tracking data.

[198] The Peninsula Corridor Joint Powers Board, which operates Caltrain, had been planning to propose a one-eighth-cent sales tax for voter approval later in the year, to provide an estimated $108 million of dedicated funding for the system, which currently relies on rider fares for 70% of its revenue.

In July, after the San Francisco Board of Supervisors initially declined to consider the ballot proposal, citing concerns about the system's governance structure, Caltrain officials warned that the agency would run out of operating funds and be forced to suspend service by the end of the year.

[199][200][201] In August, San Mateo County officials agreed to make Caltrain more independent from SamTrans in exchange for places the sales tax on the ballot.

[210] On February 24, House Speaker Nancy Pelosi toured San Francisco's Chinatown to support local shops that had seen declining business since the epidemic began in China.

[214] City of Berkeley posted signs with numbers of people allowed on the playgrounds and reminding users to maintain social distancing and limits.

[223] After Santa Clara County banned all large gatherings larger than 1,000 people for a three-week period beginning March 11, the San Jose Sharks of the NHL and the Golden State Warriors of the NBA announced that all of their remaining home games of the regular season would be played behind closed doors with no spectators.

[226] Stanford University announced plans to cut 11 of its 36 varsity sports at the end of the 2020–21 school year, citing a $70 million deficit due to the pandemic.

At the peak of the pandemic, the department operated one of the largest vaccination sites in the United States, serving about 14,000 patients per day at Levi's Stadium.

Other vaccination sites, including those at the Santa Clara County Fairgrounds and San Antonio Shopping Center, are scheduled to operate until the end of the public health emergency on February 28, 2023.

[239] The Bay Area–wide shelter-in-place order resulted in significant a reduction in road traffic volume, the main source of air pollution in the area.

[245] However, traffic volumes and congestion may return to normal levels or worse after the shelter-in-place orders are lifted, due to the avoidance of public transportation.