Special Report

This Is the County in the San Francisco-Oakland-Berkeley, CA Metro Area Where COVID-19 Is Growing the Fastest

After adding over 1,076,000 new cases throughout the last week, the U.S. now has more than 41.2 million confirmed cases of COVID-19. There have been more than 650,000 COVID-19-related deaths — the highest death toll of any country.

New cases continue to rise at a steady rate. In the past week, there were an average of 49.5 daily new coronavirus cases per 100,000 Americans — essentially unchanged from the week prior, when there were an average of 45.4 daily new coronavirus cases per 100,000 people.

While COVID-19 has spread to nearly every part of the country, cities continue to be the sites of major outbreaks. Experts agree that the virus is more likely to spread in group settings where large numbers of people routinely have close contact with one another, such as colleges, nursing homes, bars, and restaurants. Metropolitan areas with a high degree of connectivity between neighborhoods and a large population may be particularly at-risk.

The San Francisco-Oakland-Berkeley, CA, metro area consists of Alameda County, Contra Costa County, San Francisco County, and two other counties. In the past week, there were an average of 15.5 new coronavirus cases every day per 100,000 San Francisco residents, less than the national figure. The metro area’s average daily case growth in the most recent week is a decrease from the week prior, when there was an average of 27.4 daily new cases per 100,000 San Francisco residents.

The spread of coronavirus depends on a variety of factors and can vary even between neighboring counties. Within the San Francisco-Oakland-Berkeley metro area, COVID-19 is growing the fastest in Alameda County. There were an average of 19.0 new cases per day per 100,000 residents in Alameda County during the past week, the most of the five counties in San Francisco with available data.

Case growth in the San Francisco metro area varies widely at the county level. In Marin County, for example, there were an average of 5.0 new cases per day per 100,000 residents in the past week — the least of any county in San Francisco and far more than the case growth rate in Alameda County.

While Alameda County is driving the growth of COVID-19 in the San Francisco area, it does not have the highest incidence of cases overall. As of September 16, there were a total of 6,807.2 confirmed cases per 100,000 residents in Alameda County, the second most of the five counties in the metro area. For comparison, the U.S. has so far reported 12,697.8 cases per 100,000 Americans nationwide.

In order to slow the spread of COVID-19, city and county governments have ordered the closure of thousands of consumer-facing businesses. These measures have led to widespread job loss and record unemployment. In Alameda County, unemployment peaked at 14.0% in April 2020. As of June 2021, the county’s unemployment rate was 6.5%.

To determine the county in every metropolitan area where COVID-19 is growing the fastest, 24/7 Wall St. compiled and reviewed data from state and local health departments. We ranked counties according to the average number of new daily COVID-19 cases per 100,000 residents in the seven days ending September 16. To estimate the incidence of COVID-19 at the metropolitan level, we aggregated data up from the county level using boundary definitions from the U.S. Census Bureau. Population data used to adjust case and death totals came from the U.S. Census Bureau’s 2019 American Community Survey and are five-year estimates. Unemployment data is from the Bureau of Labor Statistics and is not seasonally adjusted.

These are all the counties in California where COVID-19 is slowing (and where it’s still getting worse).

Rank in MSA County Population New daily cases per 100,000, week ending September. 16 New daily cases per 100,000, week ending September. 9 Cumulative cases per 100,000 Cumulative deaths per 100,000
1 Alameda County 1,656,754 19.0 23.8 6,807.2 80.3
2 Contra Costa County 1,142,251 16.3 46.6 8,111.9 79.5
3 San Francisco County 874,961 13.4 20.6 5,590.4 68.9
4 San Mateo County 767,423 12.8 20.8 6,583.7 78.6
5 Marin County 259,943 5.0 9.6 6,369.5 93.1