Coronavirus transmission rates are falling across California, bringing guarded optimism
After weeks of an unprecedented spike in coronavirus cases that challenged hospitals, schools and other institutions, there are growing indications that the surge spawned by the Omicron variant is flattening and, in some parts of California, even beginning to wane.
Health officials in San Francisco said Thursday they believe they’ve passed the peak of the latest wave. And in Los Angeles County, there’s cautious optimism that the days of exponential growth may be in the rearview mirror.
But officials warn that hospitals will continue to face significant challenges in the coming days and weeks, and that Californians need to keep their guard up.
“We can now confidently say that we are on the beginning of a downward trajectory,” said Dr. Grant Colfax, San Francisco’s director of health. According to state data, San Francisco averaged nearly 2,700 cases a day from Jan. 3 to Jan. 9 but is now averaging about 2,000 cases a day.
But he added, “The surge is not over yet. ... Hospitalizations, which trail the peak in cases, will still continue to go up. We are urging people to remain particularly vigilant for a little bit longer. Cases are still very high.”
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School outbreaks appear to be low, but it’s hard to know given the difficulty of contact tracing.
The California COVID Assessment Tool, published by the state Department of Public Health, estimates that the state’s effective transmission rate as of Thursday was 0.77, meaning each infected Californian is transmitting the virus to fewer than one person, on average.
A rate that’s substantially less than 1.0 indicates the virus’ spread is decreasing.
However, as has often been the case throughout the two-year-old pandemic, the picture is not uniform. Out of five state-defined regions, two — the San Francisco Bay Area and Southern California — have estimated effective transmission rates are below 1.0.
While California continues to see disturbing rises in COVID-19 hospitalizations and deaths, there are some early signs the Omicron wave is slowing.
Both the San Joaquin Valley and Greater Sacramento are hovering around that baseline, meaning spread is likely stable. And in rural Northern California, the estimated rate is 1.15, which indicates increasing spread.
But conditions in the Bay Area and Southern California — two regions hit early and hard by Omicron — may foreshadow similar trends elsewhere.
“I don’t think we’re yet on the downslope,” L.A. County Public Health Director Barbara Ferrer said Thursday. “I’m hopeful that we’re plateauing, but we’ll know more by the weekend as we follow the data for the rest of this week.”
L.A. County coronavirus cases may have peaked last week, at nearly 42,000 a day. The county is now averaging about 36,000 cases a day.
While it may take a few days to account for backlogs from the Martin Luther King Jr. holiday weekend, California’s daily case count has decreased recently.
According to data released Thursday that reflect numbers through Wednesday, California was averaging 104,000 cases a day for the most recent seven-day period, a 13% drop from the prior week’s rate of 120,000. At what may prove to be the peak of the Omicron wave, California’s daily case rate fluctuated between 120,000 and 122,000 — the highest of the pandemic.
The seven-day statewide positivity rate, the share of tests that confirm coronavirus infection, also has fallen from 23% to 20.7% over the last week.
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One important caveat is that reported case counts don’t capture everyone who is infected. Some people might never get tested because their symptoms are mild or nonexistent, while others may use at-home tests and not disclose their results in any official capacity.
Even if cases have topped out, it will still take time for California to shake off the worst of Omicron. Public health officials have long noted it can take weeks after infections decline for coronavirus-related hospitalizations to likewise fall.
And in the meantime, hospitals are still struggling to manage patients who need care for all reasons, not just because they’re afflicted with COVID-19. Data released this week show the total number of people hospitalized statewide is approaching the peak of last winter’s surge.
Healthcare systems are also strained by staff shortages, in part because workers may be unavailable after becoming infected.
Last week, California averaged 52,000 hospital patients daily, just under the 55,000 hospitalized for all reasons during last winter’s COVID-19 surge.
However, the latency between cases and hospitalizations may not be as long as in prior waves, given the growing indications that, for many, Omicron causes less-severe disease than the previously dominant Delta variant.
A study that analyzed more than 52,000 Omicron cases and nearly 17,000 Delta cases within the Kaiser Permanente Southern California system from Nov. 30 to Jan. 1 found that, compared to Delta, Omicron was associated with a 53% reduction in the risk of symptomatic hospitalization, a 74% reduction in the risk of intensive-care admission and a 91% reduction in the risk of death.
The median length of stay for a hospitalized Omicron patient in the Kaiser study was also significantly shorter: 1.5 days, compared to five days for Delta.
But even with Omicron’s generally milder nature, officials say the avalanche of infections in recent weeks likely means there will be more COVID-19 fatalities.
L.A. County on Thursday reported 102 new COVID-19 deaths — the highest single-day total since March 10, 2021. Of those, 90% fell ill sometime after Christmas Eve, “indicating the high likelihood of an infection with the Omicron variant,” according to Ferrer.
L.A. County is now averaging about 56 COVID-19 deaths a day; in early December, the rate was 15 deaths a day.
“Between the increases in deaths and hospitalizations, there should be no place for complacency,” she said. “While Omicron is not causing the same proportion of severe illness as last winter ... it is substantially increasing cases of severe illness. And for a growing number of L.A. County individuals, Omicron has now become a critical matter of life and death.”
The rise in reported cases is the fastest accumulation of infections in the history of the pandemic.
Hospitalizations are now rising at a slower rate than earlier in the Omicron wave, state data show.
As of Wednesday, 15,393 coronavirus-positive patients were hospitalized statewide, up 19% from a week ago.
That’s a far gentler rise than from Jan. 5 to 12, when the patient count swelled 49%, and the week before that, when it ballooned 69%.
“The good news is things are starting to plateau,” San Francisco Mayor London Breed said Thursday. “It doesn’t mean that we get super comfortable and take our guard down, but even though we are still seeing additional cases, even though our hospitalizations are very high, we have the capacity to handle what is coming our way.”
Orange and Riverside counties actually noted decreases in their coronavirus-positive patient counts from Tuesday to Wednesday — though it remains to be seen whether that one-day change marks the start of a larger trend.
The Omicron surge has created overwhelming demand for coronavirus tests. Laboratories and manufacturers have struggled to keep up.
Dr. Timothy D. Jenkins, area medical director and chief of staff for Kaiser Permanente San Bernardino County, said the two hospitals for the area have between 200 and 250 patients hospitalized for COVID-19, the majority of whom are unvaccinated. While hospital staff are still under strain from patients needing care, Jenkins said they’re not seeing the same numbers from last winter, when there were 450 to 500 patients.
“We have not approached those kinds of numbers in the hospital setting, either in our general care units or in our intensive care units,” Jenkins said. “And we certainly have not seen the number of deaths that we were experiencing a year ago.”
But he noted that it’s important for people to get vaccinated or boosted for COVID-19 and get their flu shot as well. He said the hospital has seen the usual winter illnesses, such as flu and pneumonia, among some patients.
According to the latest available state data, unvaccinated Californians are 4.1 times more likely to get COVID-19, six times more likely to be hospitalized and almost 18 times more likely to die from the disease than their fully vaccinated counterparts.
Statewide, 68.7% of all Californians are fully vaccinated, according to data compiled by The Times.
Earlier this month, Orange County reported that a third child under the age of 5 had died from COVID-19 complications.
However, children’s hospitals are reporting rising numbers of pediatric hospitalizations. Children’s Hospital Los Angeles is reporting 59 patients who are positive for the coronavirus, the highest number since the start of the pandemic, according to Dr. Michael Smit, the hospital’s epidemiologist. The positivity rate for children tested at the facility has risen from 17.5% in December to 51% this month, also a pandemic record.
About 1 in 5 children admitted with COVID-19 have needed to go to the pediatric hospital’s intensive care unit, with some requiring the insertion of a breathing tube.
Children’s Hospital of Orange County earlier this week reported 15 pediatric COVID-19 patients, the highest number across the pandemic. Fourteen of them were in intensive care.
Times staff writer Priscella Vega contributed to this report.
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