Positivity rate hits all-time low as testing ramps up again

At 2.8%, California’s seven-day positivity rate is lower than at any other point of the pandemic

California is testing for COVID-19 at nearly its highest rate of the pandemic, while the portion of those tests to come back positive fell to its lowest point yet Monday — signs of “real progress” in the state’s battle with the virus, Gov. Gavin Newsom said Monday.

With labs conducting an average of nearly 125,000 tests per day over the past week — including more over the past three days than any other three-day stretch — just 2.8% of those returned positive results, the lowest statewide positivity rate of the pandemic and the first time it has fallen below 3%.

Even as the average number of daily cases has plateaued around 3,500 per day — another 4,721 cases Monday kept the seven-day average at about 3,560 per day, according to data compiled by this news organization — the sinking positivity rate could indicate that increased testing is capturing more cases, rather than a specific spike in spread.

With 53 new fatalities reported Monday, that sevenday average returned to near it lowest point after a brief spike last week. There was an average of 87 deaths per day over the past week in California, down 20% from a spike six days ago. Deaths had previously fallen to about 85 per day on Sept. 10 — down from a peak of 145 per day in August — before rising back to about 110 per day last Tuesday.

It’s now been two weeks since Labor Day, but Newsom said it could be another week or two before the full effects of the holiday weekend are known.

One thing that was clear Monday: Testing efforts that had been hampered by extreme heat, poor air quality and wildfires had begun to ramp back up over the weekend. Since Friday, there have been nearly 500,000 test results reported in state: nearly 170,000 Friday, 180,000 on Saturday and 150,000 on Sunday.

“The heat dome, the heat wave, the wildfires, the air quality, it all impacted our total testing ability in this state, and we’re starting to see those number go back up,” Newsom said. “As a consequence of a substantial increase in the last few days of the number of tests conducted … you can see the seven-day average of daily tests moving back up to where we were to prethese wildfires.”

California had previously been testing about 125,000 people per day toward the end of July, reaching a peak average of close to 140,000 tests per day in the first week of August. But wildfires hit and some sites were forced to close early or not open at all. That decreased the state’s testing capacity closer to about 100,000 per day, including six days in that span with fewer than 80,000 tests.

Shortly before that, test results in California and many other states had been slow to come back, with some people waiting more than a week for their result. That backlog has been largely eliminated, Newsom said Monday.

For 70% of the tests in the state, results come back within 24 hours and another “significant” portion have them within 48 hours, Newsom said.

And there are more tests on the way: the state is still on track to add “substantial” testing capacity once it opens its own lab, where it will be able to process an additional 150,000 per day as part of a deal worth up to $1.4 billion with a Massachusetts diagnostics company.

“We are committed to increasing testing in California,” Newsom said. “We are not retreating from our testing responsibilities — quite the contrary.”

On Tuesday, Dr. Mark Ghaly, the state’s top health official, was expected to announce the latest movement among the four color-coded tiers in the state’s reopening plan.

There have been two updates since the new plan was announced at the end of August, but this will be the first in which counties are eligible to move between the three more lenient tiers. Previously counties had only been able to move from Tier 1 to Tier 2, which allows for limited capacity operations in most sectors, but no further because of a three-week minimum stay at each tier level.

As a state, California would almost qualify to move on from the top, purple-colored reopening tier, where metrics say the virus is “widespread.”

At 2.8%, its positivity rate is lower than all of Tier 2 and qualifies for Tier 3, or “moderate” spread, but its per-capita case rate of about 9 per 100,000 residents per day still exceeds the threshold to move into the second tier.

However, tiers are decided on a county-by-county basis, and both Ghaly and Newsom have indicated they expect to see some locales shift between the red, orange and yellow tiers for the first time.

Since the blueprint was announced, Santa Clara and Marin counties have since joined San Francisco and Napa as the only counties in the Bay Area to qualify for the second tier.