Here’s how Delta surge compares to the last 2 times California tightened COVID rules

As the Delta variant fuels rapid increases in COVID-19 cases across virtually every corner of California, it remains to be seen whether the state will retake the reins with broad restrictions, or the burden to curb spread will stay on individual counties as it has been since mid-June.

Gov. Gavin Newsom dodged that question Monday, instead emphasizing the importance of getting vaccinated.

Newsom called more local measures “inevitable” if virus case rates continue to rise, but did not say whether new statewide rules, such as indoor mask requirements or recommendations for the fully vaccinated, were on the table.

Already, well over a dozen counties combining for more than half of California’s 39.5 million residents have, in the past week, either strongly recommended or, in the case of Los Angeles County, mandated masks in public indoor settings regardless of vaccination status.

Counties that have done so, including Sacramento, Yolo, Fresno, Stanislaus and most of the Bay Area, have cited growing local case rates amid increasing prevalence of the Delta variant as the cause for the renewed advisories. COVID-19 vaccines are highly effective but not 100%, meaning higher community transmission rates are putting even the fully vaccinated at higher risk than they were a few weeks ago.

California on June 15 dropped most pandemic restrictions, including most mask requirements for the fully vaccinated, effectively declaring the state open for business. The Golden State’s COVID-19 infection rates were near record lows around that time.

But over the course of last month, the highly contagious Delta grew to become the dominant COVID-19 variant spreading in California, as well as nationwide. In its latest update Thursday, the California Department of Public Health said Delta made up 49% of cases from June tested for variants, up from 6% in May and 2% in April.

California’s overall test positivity for COVID-19 has more than quadrupled in the past four weeks: it doubled from 1% to 2% in two weeks, then from 2% to 4% in 10 days, another worrying indicator of spread intensifying and accelerating. CDPH reported the metric Tuesday at 4.2%.

In Sacramento County, where residents are fully vaccinated at a rate a few percentage points below the state average, the local health office reports the rate of daily new cases has more than tripled in the past four weeks, from about 61 to 222 as a seven-day average. Positivity has also tripled, from 1.7% to 5.9%.

Both statewide and in Sacramento, the number of hospitalized virus patients has doubled in less than three weeks.

The increase hasn’t been centered in any one part of California: Between June 14 and July 14, hospital tallies increased by more than 10% in 30 of the state’s 38 counties that have at least 100 hospital beds, by at least 50% in 23 of 38 and by double or more in 15 of 38, state data show.

Comparing Delta surge to last summer, winter of 2020

Statewide COVID-19 activity has been increasing over the past month at a pace just as rapid if not quicker, depending on the specific metric looked at, than the increases that prompted the Newsom administration to broadly tighten California’s restrictions twice last year, a Sacramento Bee review of state health data found.

The two distinct surges since Newsom issued his initial stay-at-home order in March 2020 came last summer and winter. Each followed attempts at economic reopening, and each forced the Newsom administration to backtrack on those efforts.

Pandemic rules grew stricter in July 2020, when bars and restaurants were ordered to close back down for indoor operations after briefly being allowed back open; and again in November, when Newsom pulled an “emergency brake” and plunged most of the state into the tightest tier of California’s now-retired tiered reopening framework.

The recent infection curve is more than twice as steep than in the weeks leading up to either of those shutdowns, and the hospitalization curve comparable to them.

Positivity, a key metric used to measure spread while controlling for differences in the raw number of tests conducted, has soared from 1% to 4.2% in four weeks, state health officials reported Tuesday. Positivity increased from 5.8% to 9.6% in the four weeks before the July tightening, and from 3.1% to 5.7% ahead of the “emergency brake” order.

As of Tuesday, 19 counties including Sacramento, El Dorado, Riverside, San Diego and Contra Costa recorded positivity above 5%, according to CDPH data. Positivity is highest in Lake (12.8%), Yuba (9.8%), Humboldt (8.5%), Sutter (7%) and Mendocino (6.4%).

The number of confirmed COVID-19 patients in hospitals statewide has doubled since July 1 from about 1,070 to 2,160, CDPH reported Tuesday.

Hospitalizations doubled in about the same amount of time last November, from roughly 2,500 to 5,000 — then surged in the next six weeks to nearly 22,000, leaving intensive care units in parts of Southern California and the San Joaquin Valley with zero capacity for weeks during winter.

State and local health officials in the Sacramento region have recently said the surge in cases isn’t currently threatening to overwhelm hospital systems.

However, Sacramento County health officer Dr. Olivia Kasirye reminded during a call with reporters last week that the disease appears to be following the same general timeline it has throughout the pandemic: cases show up in test results roughly two weeks after initial exposure, and severe cases typically end up hospitalized about two weeks after that.

That means if and when any more restrictive protocols are imposed, it would take about four weeks to see it potentially reflected in hospitalization numbers.

In Yolo County, which recommended universal indoor masking a day ahead of Sacramento, health officer Dr. Aimee Sisson said in a statement last Wednesday that she was “erring on the side of caution to slow the spread” of Delta.

“We know that our vaccines, while highly effective, aren’t perfect,” Sisson said. “Putting on a mask indoors in settings where you can’t be sure that everyone who is unmasked is fully vaccinated is a simple way to add another layer of protection.”

What’s different this time around?

There are a few key factors aside from the presence of the infectious Delta variant that distinguish this surge from previous ones.

For one, COVID-19 vaccines are now widely available, and more than 60% of the state’s residents have now had at least one dose. As 2020’s summer and winter surges took hold, those vaccines had not yet been authorized.

But that makes the current surge concerning in its own right. Even with nearly 21 million residents now fully vaccinated, California is recording its highest positivity rate since mid-February, when only about 2 million were vaccinated.

On the other hand, the state did also enter the current surge from a much lower baseline of activity. California’s test positivity bottomed out last month at 0.7%, a record low for the entire pandemic, before starting its steep incline.

And finally, the dropping of most restrictions on June 15 represented a much more substantial move toward normalcy than the gradual reopening steps that preceded the July and November shutdowns.

California last month retired a “blueprint” framework that had set the rules for phased economic reopening for nearly 10 months, and significantly loosened the mask mandate for the first time, almost exactly one year after it was first ordered. Newsom marked June 15 with a celebratory speech — in front of minions from the “Despicable Me” franchise — at Universal Studios Hollywood.

Reversing course just weeks after such a display and after anticipation had built up all spring, even if warranted by skyrocketing COVID-19 numbers, would be a difficult about-face for California, which has spent the past 16 months whipsawing between tighter and looser protocols.

Andrew Noymer, an infectious disease expert at UC Irvine, recently told The Bee that it would be hard to “throw down a big public-health order one month after lifting it.”

Where do California vaccination rates stand?

About 61% of Californians have had at least one dose, and 53% of residents are considered fully vaccinated, meaning they are at least two weeks beyond their final dose.

However, that still leaves millions statewide who have no protection via vaccine, including children younger than 12 who are not yet eligible. Vaccinations have been widely available for Californians 16 and older since mid-April, and for ages 12 through 15 since mid-May.

And with vaccine rates varying widely by region, health officials expect poorly vaccinated counties could see case rates climb far higher than those with higher percentages protected as Delta continues to spread.

Sacramento County trails California by a few percentage points, recently hitting 48% of its population fully vaccinated, CDPH data updated Tuesday show.

The seven counties reported by CDPH as having the highest recent positivity rates are all below the statewide average, some of them far below. About 50% of residents are fully vaccinated in Humboldt and Mendocino counties, CDPH figures show. They are followed by Sacramento and Nevada counties at 48%, Lake County at 40%, Sutter County at 38% and Yuba County at 31%.