COVID-19 deaths in California among vaccinated rose sharply with omicron

During a three-week stretch at the height of this winter’s devastating omicron case surge, Santa Cruz County health officials lost 10 patients to COVID-19. All but one were vaccinated, and five had received booster shots.

As the omicron wave recedes, California data reveal an unsettling trend. Compared to the delta variant case surge last summer, deaths among the vaccinated rose sharply with omicron, a variant said by many experts to cause milder illness.

A Bay Area News Group analysis of state COVID-19 deaths found that in the four deadliest weeks of the delta and omicron surges, the number of unvaccinated people who died were nearly identical, and far higher than the totals for the vaccinated. Even so, three times more vaccinated people died during the omicron peak than during delta’s heyday.

“We’ve seen some chinks in the armor of vaccines that we didn’t see before,” said Santa Cruz County Deputy Health Officer Dr. David Ghilarducci. “As good as the vaccines are, they’re not 100% protection.”

More breakthrough infections, hospitalizations and deaths among the vaccinated have added to the challenges Ghilarducci and other public health officials face as they continue urging vaccination as the most effective defense against the virus, including variants like omicron.

“When I first saw that,” Ghilarducci recalled of the 10 Santa Cruz County COVID-19 patients who died from Jan.16 to Feb. 10, “I thought, ‘Oh no, what’s going on here?’”

It turned out the tragic outcomes in Santa Cruz County weren’t quite as alarming as the numbers suggested. Of the vaccinated patients who died, one was in his early 100s, three were in their 90s, two were in their 80s, three were in their 70s and most had underlying health problems. The unvaccinated man who died was in his 50s.

State figures have consistently shown the coronavirus is deadlier with age. Of the nearly 85,000 Californians who’ve died of COVID-19, 71% were age 65 or older and 92% at were least 50.

But state data also show that string of Santa Cruz County deaths among vaccinated residents wasn’t a fluke.

From Aug. 25 to Sept. 21, the deadliest four weeks of the delta surge when the variant accounted for 98% or more of genetically sequenced cases, 2,917 unvaccinated and 533 vaccinated people died.

From Jan. 14 to Feb. 10, the deadliest period of the omicron surge when the variant was 98% or more of sequenced cases, 2,999 unvaccinated and 1,767 vaccinated people died, including 436 who’d received booster shots to shore up waning vaccine protection.

Dr. George Rutherford, an infectious disease expert at UC-San Francisco, said the raw numbers make the deaths among the vaccinated look worse than they are — their rates of dying remain far less than the unvaccinated. Even the United Kingdom’s 95-year-old Queen Elizabeth II, who tested positive for the virus last month and is reported to be vaccinated and boosted, has only mild cold-like symptoms.

That is true. But the advantage for vaccinated and boosted people dropped dramatically with omicron. On Nov. 1, the seven-day average deaths per million among unvaccinated people were 38 times higher than for those who are vaccinated. But state figures show seven-day average deaths per million for unvaccinated people are only 17 times higher now than for the vaccinated and boosted.

What explains the shift? Dr. Errol Ozdalga, a hospitalist at Stanford who has been caring for COVID-19 patients throughout the pandemic, said omicron brought a wave of immunocompromised people to the hospital infected with the virus, many of them vaccinated, unlike anything he’d seen before . With delta, and earlier infection waves before vaccines were widely available, many of those who were admitted were otherwise healthy.

“That went away with omicron,” Ozdalga said. The variant has afflicted those with weakened immune systems, those who were “predisposed in some way” to severe illness, he said.

That doesn’t mean omicron is deadlier than first believed. But far more people were getting sick during the peak of the omicron surge in January, when state figures show more than 100,000 new cases were being detected daily.

By comparison, during the delta peak last summer, fewer than 25,000 people were testing positive daily. During the first winter case surge of 2020-2021, daily new cases neared 50,000. Average daily deaths peaked in the winter of 2020-2021 at over 500, during delta daily deaths peaked at nearly 140, and the most recent data on omicron suggests daily deaths peaked at just over 200 in early February.

Dr. John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology at UC Berkeley’s School of Public Health, said the sheer number of infections from fast-spreading omicron led to more deaths.

“There were more cases at the peak of omicron than with the peak of delta plus the peak of the previous year and then some,” Swartzberg said.

Ghilarducci said that unlike delta and earlier variants that caused severe infection deep in the lungs, omicron tends to cause upper respiratory illness more like a cold. But for the aged and vulnerable, that still can be too much for them. And Swartzberg added that omicron “is still a serious infection,” worse than the flu, and more capable of evading the vaccines’ protection than earlier variants.

Ghilarducci noted that as rates of vaccinations rise, there are fewer unvaccinated people left to infect. More than 70% of all Californians have now gotten the shots, up from 56% Sept. 1. And Santa Clara County Health Officer Dr. Sara Cody noted that vaccination rates are higher among older people, so those who are more at risk to begin with also are more likely to be vaccinated. But as the omicron experience shows, especially for older people, vaccination isn’t always enough.

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