Despite protests and reopening, Bay Area COVID-19 data is stable for now

As other areas in the state and country see evidence of dramatically increased coronavirus transmission, key metrics in the San Francisco Bay Area remain largely encouraging.

Despite the increase in cases, the number of hospitalizations, and the percentage of positive tests, a pair of metrics considered the best way to measure spread by UCSF epidemiologist Dr. George Rutherford are declining or stable in most of the Bay Area counties.

“The easiest thing to see is the case count, which is not a perfect metric as you have to take into account the increased evidence,” Rutherford told SFGATE earlier this month. “We are finding more asymptomatic cases now, so it is not exactly comparable to March and April, when the majority of cases detected were symptomatic. Now, in May and June, we are detecting more asymptomatic cases, so it can be difficult to interpret as ‘we are finding more infections’.

RELATED: Cheat Sheet: How to Decrypt Your County’s COVID-19 Data

Marin County is the only Bay Area county that has seen an increase in both hospitalizations and the percentage of positive tests in the past two weeks, and even with a new seven-day average of 6.6 percent positivity. in testing, the county remains below the 8.0 percent benchmark. State officials have set a goal for counties to remain low.

Although the test positivity rate is increasing slightly in some Bay Area counties, the increase is small compared to what is happening in other parts of the country. Specifically, Florida’s test positivity percentage has increased from 2.0 percent to 16.1 percent in a matter of weeks, and in Arizona that number has increased single-digit low digits to 19 percent in the same time period. .

Here is a county-by-county look at hospitalization numbers and percent positivity. All data comes from each county’s websites and the state’s database for hospitalizations by county.

San Francisco (3,249 confirmed cases)

Seven-day average for hospitalizations on June 8: 39 patients

Seven-day average for hospitalizations on June 22: 35.6 patients

Seven-day average for positive test rate percentage on June 8: 1.6 percent

Seven-day average for positive test rate percentage on June 21 *: 2.0 percent

* San Francisco test data only runs through June 21

San Mateo (2,961 confirmed cases)

Seven-day average for hospitalizations on June 8: 55.1 patients

Seven-day average for hospitalizations on June 22: 23.3 patients

Seven-day average for positive test rate percentage on June 8: 3.5 percent

Seven-day average for positive test rate percentage on June 22: 4.4 percent

Alameda (5,140 confirmed cases)

Seven-day average for hospitalizations on June 8: 87.4 patients

Seven-day average for hospitalizations on June 22: 81.9 patients

Seven-day average for positive test rate percentage on June 8: 3.9 percent

Seven-day average for positive test rate percentage on June 22: 3.5 percent

Against Costa (2,454 confirmed cases)

Seven-day average for hospitalizations on June 8: 17 patients

Seven-day average for hospitalizations on June 22: 29 patients

Seven-day average for positive test rate percentage on June 8: 4.7 percent

Seven-day average for positive test rate percentage on June 22: 3.2 percent

Santa Clara (3,727 confirmed cases)

Seven-day average for hospitalizations on June 8: 65.6 patients

Seven-day average for hospitalizations on June 22: 56 patients

Seven-day average for positive test rate percentage on June 8: 1.5 percent

Seven-day average for positive test rate percentage on June 22: 2.0 percent

Marin (984 confirmed cases)

Seven-day average for hospitalizations on June 8: 1.7 patients

Seven-day average for hospitalizations on June 22: 6.1 patients

Seven-day average for positive test rate percentage on June 8: 4.1 percent

Seven-day average for positive test rate percentage on June 19 *: 6.6 percent

* Marin County test data only runs through June 19.

Solano (1,020 confirmed cases)

Seven-day average for hospitalizations on June 8: 11.9 patients

Seven-day average for hospitalizations on June 22: 15.3 patients

NOTE: Solano does not report the daily percentage positive test rate, only cumulative test data.

Napa (245 confirmed cases)

Seven-day average for hospitalizations on June 8: 0.6 patients

Seven-day average for hospitalizations on June 22: 3.7 patients

NOTE: Napa does not report the daily percentage positive test rate, only cumulative test data.

Sonoma (956 confirmed cases)

Seven-day average for hospitalizations on June 8: 13.6 patients

Seven-day average for hospitalizations on June 22: 10.8 patients

NOTE: Sonoma does not report the daily percentage of positive test rate.

Rutherford told SFGATE in mid-June that it generally takes 7-10 days to measure the impact of an event, such as a protest or reopening phase, on total cases or percentage positivity numbers. Because Bay Area counties reopened in retail stores, open-air restaurants, and other sectors in early June, as protests began, we should expect to see a significant change in the percentage of positivity to these heights if these events had a major impact on broadcast.

Furthermore, most patients who end up needing hospitalization for COVID-19 reach this stage 7-10 days after the onset of symptoms, so hospitalization rates are slightly lower than other metrics.

However, Rutherford, citing data from Minneapolis, stated that there was no guarantee that protests or other outdoor activities would lead to an increase in transmission of the virus.

“Minnesota (is) falling steadily; there is a slight rebound on June 1, but that may be due to delays in reporting over the weekend,” he said two weeks after protests over the death of George Floyd began in Minneapolis on May 25. “But everything tends to go down. If you look back seven to 10 days, you would expect to see a significant jump right now.”

Because the protesters did not maintain a physical distance of six feet but many wore masks, Rutherford believes there is a clear conclusion.

“Masks work,” he said. “Masks are the most important thing. I would say that masks go beyond social distancing in terms of practical protection. And outdoors, where the virus is not held by four walls, a ceiling and a floor also help … This It is not a great science and nobody is going to win the Nobel Prize for it, but if you have a great increase in activity, and after seven to 10 days after the event, not much transmission was transmitted, that is nothing. “

Eric Ting is a digital reporter for SFGATE. Email: [email protected] | Twitter: @_ ericting

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