Another month, another phase of the pandemic — and a new state “blueprint” for a phased economic reopening in California.
We’re tracking how the Bay Area’s nine counties are progressing through the new system announced by Gov. Gavin Newsom on Aug. 28.
To sum it up: There are four tiers — ranging from widespread to moderate — with corresponding colors (purple, red, orange, yellow) and two all-determinative metrics: the per-capita case rate and the positivity rate for PCR tests, both averaged over seven days. A third figure — the number of tests per-capita — can lower a county’s case rate in the state’s formula from between 12% and 40%. The state will update its figures every Tuesday, starting Sept. 8, and a county must meet both marks for 14 days before it is eligible to move to the next tier.
Read more about the new plan — and what it means for restaurants, offices, schools and more — here.
San Francisco and Napa were the Bay Area’s only counties in the second tier, otherwise known as substantial or red, with limited-capacity reopening permitted in many sectors (but local stricter orders still enforced), when Newsom announced the initial tiers. Everywhere else was, like much of the state, in Tier 1, known as widespread or purple, with many sectors of their economies shut down or severely limited.
Upon the first update, Santa Clara County was one of five counties to move from Tier 1 into Tier 2.
As of Tuesday, Sept. 8, a number of Bay Area counties — San Francisco, Santa Clara, Napa and Solano — met both thresholds for tier two, according to our data, but Solano didn’t make the cut for Newsom’s Tuesday afternoon update. Alameda, San Mateo and Marin were below the positivity rate threshold but just above the case rate cut off, according to our data. San Francisco, Santa Clara and Alameda have also tested enough for an adjustment to kick in and lower their case rates.
In the last official update from the state, five counties moved from Tier 1 into Tier 2, including Santa Clara County. Now, there are 33 counties in the most severe grouping and 14 counties in Tier 2. Another nine were in Tier 3, and two remote mountain counties — Alpine and Modoc — were in the lowest of the four tiers. The next update is due Tuesday.
Note: CDPH dates cases to its earliest known infection and uses a seven-day lag, while this news organization tracks them in real-time when they are reported by the county health department. CDPH also separates inmate populations, while this news organization does not, leading to higher rates represented here in Marin County than in CDPH data because of San Quentin State Prison.
Last updated: Tuesday, Sept. 8
Case rate adjustment multiplier: < 2.4 tests/1,000 population = no adjustment; 2.41-2.99 = 0.88; 3-3.59=0.78; 3.6-4.19=0.71; 4.2-4.79=0.65; > 4.8 = 0.6
Alameda
Cases per 100,000 per day (past 7 days): 9.6
Tests per 1,000 per day (past 7 days): 3.7
Case rate adjustment multiplier: 0.71
Adjusted per-capita case rate: 7.7
Positivity rate: 2.6%
Contra Costa
Cases per 100,000 per day (past 7 days): 9.5
Tests per 1,000 per day (past 7 days): 1.3
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 9.5
Positivity rate: 7.5%
Marin
Cases per 100,000 per day (past 7 days): 7.3
Tests per 1,000 per day (past 7 days): 0.9
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 7.3
Positivity rate: 7.7%
Napa
Cases per 100,000 per day (past 7 days): 3.5
Tests per 1,000 per day (past 7 days): 1.4
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 3.5
Positivity rate: 2.4%
San Francisco
Cases per 100,000 per day (past 7 days): 7.8
Tests per 1,000 per day (past 7 days): 4.7
Case rate adjustment multiplier: 0.65
Adjusted per-capita case rate: 5.0
Positivity rate: 1.7%
San Mateo
Cases per 100,000 per day (past 7 days): 8.2
Tests per 1,000 per day (past 7 days): 0.8
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 8.2
Positivity rate: 6.0%
Santa Clara
Cases per 100,000 per day (past 7 days): 9.9
Tests per 1,000 per day (past 7 days): 6.0
Case rate adjustment multiplier: 0.6
Adjusted per-capita case rate: 6.5
Positivity rate: 2.8%
Solano
Cases per 100,000 per day (past 7 days): 5.1
Tests per 1,000 per day (past 7 days): 0.8
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 5.1
Positivity rate: 6.4%
Sonoma
Cases per 100,000 per day (past 7 days): 18.5
Tests per 1,000 per day (past 7 days): 1.4
Case rate adjustment multiplier: n/a
Adjusted per-capita case rate: 18.5
Positivity rate: 13.5%
Official map, as of Aug. 31, with data as of Aug. 18
