California coronavirus testing amid Delta variant: Key takeaways

A medical professional gives a coronavirus test to a student.

Aug. 17, 2021 9:17 AM PT

There are early indications that California is making progress in its fight against the Delta variant of the coronavirus.

But much uncertainty remains.

While some of the state’s most populous regions have recently recorded slowdowns — even a flattening — in how many new coronavirus cases being reported day over day, it remains to be seen whether that forecasts a wider trend.

Clouding the coronavirus crystal ball is the expected ramping up of California testing as schools around the state reopen. Tens of thousands of students, faculty and staff members will have to be regularly tested, even if they don’t exhibit any signs of infection — boosting the likelihood that more asymptomatic cases will be uncovered.

Some government and private employers also are imposing testing requirements for workers who have yet to be vaccinated against COVID-19, deepening the testing pool further.

“As our businesses, schools and institutes of higher education are putting back in place, or setting up, routine testing screening programs, we expect to see hundreds of thousands [of] more test results each week. And, in parallel with that big an increase, we’re bound to see increases in cases,” Los Angeles County Public Health Director Barbara Ferrer said.

A more accurate picture

That’s not to discount the case counts.

Rather, Ferrer said robust testing will help paint a more complete picture of how widespread coronavirus transmission is — and help keep residents from serving as unwitting viral vectors.

“It’s a good strategy for reducing transmission overall and slowing the spread,” she told reporters during a recent briefing. “But it will have the impact of increasing our numbers. So, in part, that’s what we’re seeing.

“It still means there is a lot of community transmission going on, and we all need to take additional safety precautions.”

Cases vs. positivity rate

Another important metric to track is test positivity, the rate at which conducted tests are confirming coronavirus infections.

While the number of tests being conducted statewide has risen sharply in recent weeks, test positivity has actually dipped. As of Monday, the seven-day positivity rate was 6.1%, down from 6.7% two weeks ago, state data show.

“If you had a lot more testing, and test positivity went up, that would just say you’ve got a lot more transmission going on,” Ferrer said.

“If you have a lot more testing, and test positivity remains flat or declines a little bit, it means that community transmission is either stable or may, in fact, be declining slightly,” she added.

Trends

California is now reporting about 12,100 new coronavirus cases a day over the last week, up 9% from the previous week, according to a Los Angeles Times analysis.

That’s a far slower pace of increase than in the previous week, when there was a 30% jump in daily cases, and much better than in early July, when there was an 86% week-over-week increase. Daily cases remain far below the pandemic peak of nearly 45,000 new cases a day.

L.A. County was one of the first areas of the state to document the latest spike, and officials in late June began urging all residents, regardless of vaccination status, to wear masks in indoor public places as a precaution.

In recent weeks, county officials have said their case counts have increased at a lower rate than the rest of the state — a development they partially attributed to universal public indoor masking, which has been required in the region since mid-July.

Over the last seven days, L.A. County reported an average of 3,362 new cases per day: a less than 1% increase from the week prior, Times data show.

State health officials are also now recommending indoor masking while in public, and a host of individual counties have opted to mandate the practice.

But while non-pharmaceutical interventions such as face coverings and maintaining physical distance can help stymie the spread, officials say the surest way to beat back the coronavirus is to vaccinate as many people as possible.

So far, more than 63% of Californians have already received at least one dose, Times data show, and 55% are fully vaccinated.

However, that still leaves millions of people who, either by choice or circumstance, have yet to roll up their sleeves. Included in that group are all children under the age of 12, who are not yet eligible to be vaccinated.

Two pandemics

Those who have been fully inoculated, experts say, are not only better shielded from coronavirus infection, they’re far less likely to become seriously ill from COVID-19.

For the week ending Aug. 7, the average case rate among uninoculated Californians was 51 per 100,000 people per day — more than six times the rate for those already vaccinated, according to figures from the state Department of Public Health.

The vast majority of COVID-19 patients winding up in hospitals statewide are also unvaccinated, officials say. In L.A. County, officials said vaccinated people are about 14 times less likely to be hospitalized.

While the overall healthcare system is not as deluged as during California’s fall-and-winter surge — when roughly three times as many coronavirus-positive patients were receiving professional care — hospitals are feeling the pinch.

“What is really happening is a real challenge with staffing overall,” said Jan Emerson-Shea, a spokeswoman for the California Hospital Assn., a trade group that represents more than 400 facilities. “And that is an area that is becoming of great concern across the state.”

Even before the latest surge struck, she said, hospitals were contending with a backlog of people who had put off non-COVID-related care earlier in the pandemic.

“Now they may need that knee replacement surgery or the gallbladder out,” she said. “Those procedures were starting to come back, and now COVID is rising.”