California's COVID test positivity rate quadruples in last two weeks

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ByLiz Kreutz KGO logo
Wednesday, December 29, 2021
CA's COVID test positivity rate quadruples in last 2 weeks
New data from the California Department of Public Health shows the positivity rate in the state is 9.7% -- the highest it's been in months.

SAN FRANCISCO (KGO) -- COVID-19 cases are rising rapidly across California.

New data from the California Department of Public Health shows the positivity rate in the state is 9.7% -- the highest it's been in months.

That number is more than four times what it was two weeks ago. On December 15, the state positivity rate was 2.3%.

"If you're like me, you're getting calls from friends and relatives more than you ever have over the past two years about, 'I got it. I was exposed to it. What do I do?'" Dr. Bob Wachter, the chair of UCSF's Department of Medicine, told ABC7 News. "And that's even in vaccinated people, so it is clear that we're going to see a lot of cases."

Every county in the Bay Area is seeing a surge.

In San Francisco, a spokesperson for the San Francisco Department of Public Health said cases are rising three times faster than during the summer delta-fueled surge. In the 7-days ending on December 20, the case rate tripled from 91 cases to more than 273 cases.

Currently, there's an average of more than 300 cases per day.

RELATED: Bay Area counties report record-breaking number of daily, weekly COVID cases

"On Christmas day, and gatherings that occurred just before Christmas, have yielded another surge on top of the surge we're already seeing," Marin County Public Health Director Dr. Matt Willis told ABC7 News.

Dr. Willis said he expects Marin County to hit a record for cases in the county.

"This morning we found 300 new cases in the cue that had accumulated yesterday afternoon through the night," Dr. Willis said. "We're on track for another record setting day in terms of case numbers."

There are some silver linings. Despite the rising cases, hospitalizations remain low. Marin County has just four people in the hospital despite rising cases.

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Transmission is also much lower among those who are vaccinated.

In this graph from Marin County, the blue shows transmission among vaccinated people and the orange shows transmission among unvaccinated people.

The same with this graph from Alameda County. The blue line is vaccinated people and the yellow line is unvaccinated people.

"It does seem like the main thing that protects people is the level of immunity they have," Dr. Wachter said. "And it looks, so far, that with omicron you're going to see a lot of cases and a lot of illness, but if you've had two shots and particularly three shots, you have a very high level of protection to prevent you from needing to go to the hospital and getting very sick and dying."

VACCINE TRACKER: How California is doing, when you can get a coronavirus vaccine

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