Coronavirus Tracker The Chronicle is mapping every reported coronavirus case in the Bay Area, California and the U.S. We are tallying the number of confirmed cases, deaths, hospitalizations and tests reported across the state by day, and tracking how Bay Area counties are progressing on criteria for reopening.

What are the latest developments? Coronavirus-related deaths in the United States surpassed 200,000 on Tuesday, accounting for more than 20% of reported deaths worldwide. With nearly 7 million reported cases, the U.S. also accounts for nearly 22% of infections globally. As cases and deaths continue to rise, the Centers for Disease Control and Prevention continues to waver in its guidance on how to fight the virus. Monday’s reversal concerning airborne transmission alarms Bay Area experts and “raises the possibility of political pressure altering what is on their website,” said Michael Lin, associate professor of neurobiology and bioengineering at Stanford. With the arrival of flu season, here’s what we know about the combination of flu and coronavirus, including where to get your annual shot. For the latest news and developments, read The Chronicle's coronavirus live updates or sign up for our coronavirus newsletter. New reported cases and deaths in the Bay Area, by day New reported cases and deaths in California, by day Sources: U.S. Centers for Disease Control and Prevention, California Department of Public Health and county public health departments, Chronicle reporting



The seven-day trailing average represents the average number of cases or deaths reported each day over the weeklong span ending on the given day. It is used to account for daily variances in reporting and large one-off changes in daily counts, such as April 20 when nearly 1,500 cases were reported in L.A. County as the result of a lab clearing a large backlog. Some counties do not provide daily updates which, combined with daily variances in the number of tests given, could result in randomly higher or lower counts for daily reported cases.

Where do Bay Area counties stand in reopening? Alameda, San Mateo and Solano counties joined San Francisco, Santa Clara, Marin and Napa in the red tier of the state’s new reopening plan. That leaves just Contra Costa and Sonoma in the Bay Area in the purple tier, which is the most restrictive and allows the fewest businesses to open. The red tier is the second of the four color-coded tiers. In conjunction with the state’s reopening plan and with county approval, thousands of San Francisco businesses reopened over the past two weeks. Schools in San Francisco and Napa counties now have state approval to open for in-person instruction without waivers, but county officials will determine when to allow students to return to classrooms. Check the reopening tracker to see what’s allowed in each tier.

What are the current trends in the Bay Area? Coronavirus cases in the Bay Area have been declining since mid-August. About 3,700 cases have been reported each of the past two weeks, which is about half the number of cases reported a month ago. According to data reported by county officials and compiled by The Chronicle, half of the Bay Area counties reported week-over-week declines in cases and half reported increases. Even with the declines, the Bay Area this week will surpass 100,000 total cases since the start of the pandemic. Bay Area cases by city or region Some Bay Area county health departments are now providing details on where people who have tested positive reside, either by region, city or jurisdiction. Use the drop down to search counties (more will be added if data becomes available). Alameda County

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How many people have been hospitalized? With fewer than 2,700 COVID-19 patients, California hospitals are reporting numbers equal to those in early April and down more than 60% from July. In the Bay Area, the number of patients has fallen to just over 400, which is down from the high of 815 on July 28. The number of ICU patients statewide has also declined 60% from a high of 2,058 in July to just more than 800 now. The ability for hospitals to handle future outbreaks is being closely monitored and will help shape California’s attempt to reopen. Due to limited testing capacity, not all hospitalized patients with COVID-19 symptoms have been tested. While not all suspected cases will ultimately test positive, including these patients may give a more comprehensive picture of the demands on hospitals. Even with suspected cases included, hospitals have not seen a surge in virus-related patients as feared.

What is the status of testing in California? The state processed more than 112,000 test results per day last week and has conducted more than 13 million tests since the start of the outbreak. The positivity rate last week was 3.0%, which is lower than the 3.6% reported the previous week and the national rate of 4.8%. The rate was up to nearly 8% in late July. The state used 8% as a goal for reopening in its original plan and now uses positivity rate along with case rate (adjusted based on testing levels) to determine tier status in the new reopening plan. As more people get tested, the positive test rate provides a more clear picture of how many people are carrying the virus, including those without symptoms, and the possibility for a second surge in cases.

How does California compare to the rest of the nation? The seven-day average for new cases in the U.S. increased by more than 6,000 per day last week, climbing from around 34,000 to more than 40,000, ending what had been a steady decline since late July. California averaged around 3,500 cases per day last week, up slightly from 3,250 the previous week. New daily cases are on par with reports from early June, prior to this summer’s big second spike in cases. In the Bay Area, cases rose from 525 per day to 540 last week. Global estimates are that nearly 70% of the more than 31 million patients who tested positive have recovered, but figures for recoveries are not available for the Bay Area or California.

Findings signal earlier start to U.S. outbreak An autopsy report showing that the first death linked to COVID-19 happened Feb. 6 in Santa Clara County and not Feb. 26 in Washington supports research indicating that the outbreak began in the United States much earlier than we knew and before health officials began tracking data. There were 300 cases reported in the Bay Area when shelter-in-place orders were put in place on March 16. But studies and disease models suggest that more than 10,000 people in the Bay Area likely were infected by then. That research, along with the earlier death identified in Santa Clara County, indicates how far behind the U.S. was in recognizing the outbreak of the virus. The data used here examines the spread of the virus and potential containment going back to when officials knew the virus had arrived in the United States. While this data is limited and flawed in its ability to give a full history of the virus, it is all health officials have and underscores the importance of increased testing to provide a clearer picture of the current situation.

Fifth & Mission Podcast Fifth & Mission is diving into all the ways COVID-19 is impacting life in the Bay Area. Listen by selecting your preferred podcast service below. Apple Spotify Overcast Google Stitcher Pocket