SACRAMENTO, Calif. — After steady decline since mid-July, some metrics of COVID-19 spread are showing early signs of plateauing in California, as transmission has begun to trend upward once again in some parts of the world.
The California Department of Public Health reported the latest daily case rate at 7.5 per 100,000 residents in a weekly update Thursday, down 13% in the past week for its lowest point since early April.
CDPH reported 1,746 virus-positive patients in hospital beds, a 7% decline in the past week and the smallest tally since mid-May.
But decline in the key indicator of test positivity has slowed, state data show. CDPH reported positivity at 4.7% as of Thursday, down minimally from 4.9% three weeks earlier. In the prior three-week stretch, from late August to mid-September, positivity fell from 8.4% to 4.9%.
The plateau comes as cases and hospitalizations with COVID-19 have spiked in recent weeks in the United Kingdom and other parts of Europe, which have often served as a bellwether for U.S. coronavirus trends, and as new subvariants continue to emerge around the world.
Health officials continue to say that vaccines, including the recently authorized bivalent booster doses that target both the original strains of COVID-19 as well as the BA.4 and BA.5 variants, remain effective.
The booster uptake rate remains low in California and across the U.S. CDPH in an Oct. 7 update reported that 28.9 million Californians have received an initial series of a coronavirus vaccine, but only 16.7 million have also received a booster dose.
California’s two worst surges to date have come the past two winters. Its deadliest wave began in winter 2020, before vaccines were widely available; and the steepest surge in terms of new infections peaked this January with the arrival of the original omicron variant, BA.1.
The omicron subvariant known as BA.5 remains dominant nationwide, reported by the U.S. Centers for Disease Control and Prevention on Friday at 68% of new cases last week.
But a handful of newer variants are making up a rapidly growing share of cases, particularly a pair of new omicron offshoots known as BQ.1 and BQ.1.1, which health experts have said appear to evade immune protection — a common trait in new variants that overtake previous ones to become dominant.
BQ.1 and BQ.1.1 have surged from a combined 2.8% of U.S. cases two weeks ago to 5.7% last week and 11.4% in this week’s update, essentially doubling in each of the past two weeks.
In the United Kingdom, national health data updated Thursday showed cases, hospitalizations and deaths all on the rise, with new infections up 21% in the past week.
The U.K. Health Security Agency in an Oct. 7 report said BQ-family variants “show evidence of a positive growth rate compared to BA.5,” as do a pair of other omicron subvariants called BA.2.75.2 and BF.7.
The report says those three variants could be at least partly responsible for the current surge, but that it remains too early in the increase to be certain.
So far in the United States, variants BF.7 and BA.2.75.2 have spread less quickly than BQ.1.1. BF.7 increased from 4.2% to 5.4% in the past week, according to Friday’s update from the CDC, and BA.2.75.2 from 1% to 1.4%.
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