Sonoma County public health officials said Wednesday that genetic testing of selected COVID-19 samples has detected at least 115 cases of the highly transmissible delta variant, a big jump from the 68 infections reported less than two weeks ago.
The finding reflects a national trend where the delta has now become the dominant coronavirus strain, said Dr. Sundari Mase, county health officer.
Medical experts in California and nationwide say the vast majority of people who become infected with the highly contagious delta variant have not been vaccinated.
For several weeks, Mase, along with state and federal health officials, has said this variant is primarily responsible for the recent rise in COVID-19 cases and hospitalizations, including in Sonoma County.
“The vast majority of our samples selected for genotyping from May onwards have been the Delta variant,” said Mase, noting that the Centers for Disease Control and Prevention reported that this strain of coronavirus accounts for 83% of infections across the country.
Of the 115 local delta cases, 48 were detected using the county’s new genetic sequencing equipment, which was used for the first time on 13 July. During the initial run, 28 of 31 COVID-19 patient samples were confirmed to be the delta strain.
Mase said not all local coronavirus samples are genotyped. Instead, the county’s public health staff prioritizes certain virus cases. They include cases found among vaccinated and non-vaccinated individuals, hospitalized patients and major outbreaks such as the recent one in Santa Rosa’s most important homeless shelter, Samuel Jones L. Hall. At least 90 residents have been infected with the coronavirus since July 2, city officials said this week.
Finally, the county expects to perform broader genetic testing of COVID-19 samples to get a better idea of how the variants spread, the health officer said.
Across the country, the number of coronavirus patients being treated in a hospital has more than doubled in one month. Infections have accelerated further in the past two weeks, according to a Los Angeles Times report.
From June 22 to July 6, the daily number of COVID-19 patients admitted to California increased from 978 to 1,228, an increase of nearly 26% according to state data. Over the past two weeks, the daily number increased by a further 76% and reached 2,164 from Monday.
The rise in cases and hospitalizations prompted Los Angeles County officials last Thursday to reintroduce a mandate for residents to wear masks indoors. The following day, Sonoma County joined six other Bay Area counties and the city of Berkeley to recommend indoor mask use.
On Wednesday, Lake County health officials also urged local residents to wear masks indoors. Health officials reported that as of Tuesday, Lake County has a coronavirus transmission rate of 17 new daily cases per day. 100,000 inhabitants, the highest in the state and almost twice as large as the average.
As of Wednesday, Sonoma County’s daily transfer rate is 9.5 cases per month. 100,000 people. To put this level of COVID-19 spread in perspective, under the state’s four-step reopening plan, which was scrapped in mid-June, a rate of 10 cases per year was scrapped. 100,000 inhabitants considered widespread transmission and would have triggered the most restrictive purple level of the state plan.
With an aggressive vaccination campaign starting in December 2020, the county is close to the 70% minimum limit for fully vaccinated people commonly referred to as herd immunity. This is the point when researchers say that coronavirus has a hard time spreading in society. As of Wednesday, 69% of residents had been fully vaccinated against COVID-19 for at least 12 years.
“We have to tell people that there is still a big risk, especially if you are not vaccinated,” Mase said. “You have a much higher risk of COVID if you are not vaccinated.”
You can reach Staff Writer Martin Espinoza at 707-521-5213 or [email protected] On Twitter @pressreno.