Coronavirus resurgence in Sonoma County outruns contact tracers

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Last summer, before coronavirus transmission became widespead throughout the community, a nimble platoon of dozens of public health workers jumped on every new case detected in Sonoma County.

Some 70 so-called contact tracers tracked viral spread in neighborhoods, vineyards, factories and day care centers. They called people who were infected and put together lists of all their potential close contacts, advised residents how to quarantine and isolate and conducted testing of those exposed to the highly contagious infectious disease.

At the time, public health staff members were detecting through COVID-19 testing between 20 and 30 new cases a day, and the goal of reaching everyone exposed by a single infection was difficult.

Today, the deadly resurgence of the pandemic disease is infecting 10 times that number of local residents, between 200 and 300 new daily cases. With the virus circulating essentially unchecked in every corner of the county, tracking every person infected is virtually impossible and even ineffective, local public health officials said.

“It’s much harder to control an epidemic and (contact tracing) is not as effective a strategy when you get to these surge levels of cases and transmission that's happening frequently in the community,” said D’Arcy Richardson, director of nursing in the county’s public health division. “Then it becomes more of a question of containing it, rather than trying to flatten that curve.”

Therefore, contact tracing has become part of a broad pandemic containment strategy centered around going into communities and settings ravaged by the virus and providing more testing, outreach and beginning to vaccinate residents.

County Health Officer Dr. Sundari Mase said Wednesday the county is now relying on large health care providers, such as Kaiser Permanente, Sutter Health and Providence St. Joseph Health, to conduct their own tracing efforts. Big employers and businesses that experience viral outbreaks are also encouraged to do their own contact tracing and provided with testing resources and information to do so.

“Definitely our partners are stepping to help us with contact tracing,” Mase said.

The county’s public health division now has between 85 and 90 health care professionals working on its contact tracing team. These include public health nurses, investigators, epidemiologists and outreach workers trying to keep up with the detective work to slow the spread of the virus.

Back in August, at the peak of the previous surge, the county had up to 105 contact tracers chasing an average of 92 daily cases. It was a dark time during the pandemic, with 43 deaths reported that month and another 42 in September. It was largely the result of COVID-19 outbreaks in skilled nursing centers and assisted living homes. In January, amid an even more grueling stretch, deaths have skyrocketed to 50, already surpassing any previous month since the pandemic began in March.

The winter deluge of new cases has dwarfed the summer wave, with an average of 258 new daily confirmed infections since 2021 started. Members of the contact tracing team are each taking on 10 new cases a day, with some cases taking longer to process than others.

“When you get to a point where there's widespread community transmission. It's not so easy to pinpoint your source or who you might have been in contact with because there are multiple potential contacts and multiple potential routes of transmission for people who are out and are essential workers,” Richardson said.

Dr. John Swartzberg, a UC Berkeley infectious disease expert, said contact tracing tactics used in the beginning of a pandemic become less effective during a surge.

“Contact tracing is not very effective when there are so many cases,” Swartzberg said. “When we are able to drive down the infection rate with other means, that's when we can effectively apply contact tracing.”

Those means include masking and social distancing, he said.

In prioritizing cases, contact tracers follow guidelines from the federal Centers for Disease Control and Prevention, focusing on people who have tested positive for COVID-19 in the past 6 days.

With so many cases, Richardson said, testing slows and the reporting of new infections is often delayed. And sometimes cases aren’t even reported to county public health officials until after those infected are finished with their isolation period. Indeed, the origin of 54% of county virus cases remain under investigation.

Of those diagnosed with the virus within six days, contact tracers try to determine if there are vulnerable people in that household, at highest risk of hospitalization or having a severe case of COVID-19.

“What we try to do is gather the essential information to determine ... and make sure that everyone who is vulnerable is informed and tested,” Richardson said.

Mase and Richardson underscored the importance of adhering to public health measures of masking, social distancing, maintaining good hygiene and staying home when sick, as the vaccine slowly make its way into the arms of county residents.

“We’re only a few bad choices away from having a situation like Los Angeles’ situation,” Richardson said, referring to following public health guidelines. “... That's what's going to help us get through this without having our hospitals overloaded, without having more people die.”

The pandemic has thus far claimed the lives of 242 county residents, including eight deaths reported since Sunday. The recent fatalities occurred between Jan. 2 and Monday and included six males and two females. Five of them were 65 or older and three were between 50 and 64.

Four of the deceased were residents of skilled nursing homes and four were among the general population.

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

Track coronavirus cases in Sonoma County, across California, the United States and around the world here.

For more stories about the coronavirus, go here.

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