New COVID-19 infections skyrocket in Sonoma County as hospital cases double in less than a week

New COVID-19 cases in Sonoma County have skyrocketed since late December, more than doubling to a pandemic record of over 90 daily cases per 100,000 residents by Jan. 1, according to the latest local public health data.

The dramatic data is a clear sign that the highly infectious omicron variant is now rampant in the community.

The number of Sonoma County residents hospitalized for COVID-19 has also quickly climbed, to 64 on Friday, more than double the coronavirus hospital census registered just four days ago, according to local public health data.

“This is what we’ve been predicting,” said Kathryn Pack, health program manager for the county’s epidemiology team. “We’ve seen a very dramatic increase in community transmission — now we’re starting to see that reflected in our hospitalizations.”

On Saturday, county health officials reported a new daily transmission rate of 91.6 cases per 100,000 residents, averaged over the seven-day period ending Jan. 1. On Dec. 26, that rate was about 43 new cases per 100,000 people.

By comparison, last year, on Jan. 8, amid the deadliest period of the pandemic, the local infection rate reached a high of 56.5 daily cases per 100,000 people.

The clearer picture of the county’s virus transmission rates came Saturday after public health staff processed an “unprecedented” volume of cases received in the past couple of days, which created a backlog in recording positive cases, Pack said.

“We are implementing a fix for that issue today,” Pack said in an email Saturday.

As late as Friday, the county was reporting an average of about 50 new daily COVID-19 cases per 100,000 residents. That rate jumped to nearly 92 on Saturday. Just three weeks ago, the transmission rate was 19 new daily cases per 100,000 people.

The county’s COVID-19 website reported 441 newly confirmed cases for Friday. But infection numbers are likely larger than what’s being officially reported, given the use of commercial rapid test kits whose results may or may not be reported in some cases.

The speed at which local COVID-19 hospitalizations have increased is dizzying. And officials say they expect the spike to continue.

County hospital data shows that on Jan. 3, there were 28 people hospitalized with COVID-19, the disease caused by the novel coronavirus. In subsequent days, the number increased to 34, 39, and 48 before reaching 64 on Friday.

County health officials had feared the number of hospitalizations would increase due to widespread COVID-19 transmission. Pack pointed out that there’s usually a weekslong lag between spikes in virus transmission and subsequent increases in COVID-19 hospitalizations. Local case rates have been climbing steadily since early December.

Pack said the share of COVID-19 patients who are currently in intensive care units — 7 out of 64, or 11% — “is still relatively low.” She also pointed out that some patients who are testing positive for COVID-19 are probably being admitted for some other condition.

“When you have very high community transmission, there is also a greater occurrence of individuals who are hospitalized for other reasons who also happened to test positive for COVID-19,” she said.

Pandemic-related hospitalizations reached a record 104 on Jan. 7, 2021, during the first winter surge. Local health officials are paying close attention to hospitalization rates, which are a key marker for assessing the severity of pandemic surges.

Pack and Dr. Sundari Mase, the county’s health officer, said they fully expect pandemic hospitalization numbers to continue increasing. Currently all patients hospitalized with COVID-19 are adults and there are no pediatric cases, officials said.

Mase urged local residents to rethink their current social behavior. That includes avoiding large and small gatherings, and continuing with pandemic-era precautions such as masking, social distancing and frequent hand washing.

Infections from gatherings of all sizes now comprise more than 50% of confirmed cases where the source of transmission has been determined, officials said. But large gatherings are beginning to play a bigger role in transmission.

“Over the last couple of weeks, the majority were large gatherings, with more than 12 individuals,” Pack said.

With cases skyrocketing — and hospitalizations now following suit — Mase said it’s a good time to exercise far greater caution.

Officials said virus transmission is so widespread that large numbers of vaccinated residents are being impacted, though not at the same rate as those who have not been vaccinated.

The current infection rate for unvaccinated residents is 100.7 new daily cases per 100,000 people, compared to 38.9 per 100,000 residents for vaccinated residents.

“People should reconsider large events or small events where there’s unvaccinated individuals,” she said. “We’ve also seen transmission in fully vaccinated settings. So really reconsidering any gatherings, whether large or small, of any sort might be appropriate at this time.”

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @pressreno.