As vaccination rates rise, COVID-19 testing is slumping, and health officials are worried.
In California, 3 out of 4 counties have seen their testing volume drop by at least 15 percent.
"There used to be 5 or 6 people ahead of me, and lately it's down to no one, I just walk right in," said Brad Jann, getting tested at the Petaluma Fairgrounds on Friday evening.
Jann is a podiatrist who must be tested weekly in order to care for his patients who live in retirement communities.
"I'm exposed to so many seniors and I go to so many facilities, if I'm positive and I don't test, I can carry the virus from place to place," he explained.
Sonoma County's test volume has plunged 28 percent, rivaling the overall state decline of 32 percent.
"There are many, many testing opportunities people should use," said Sonoma County's Public Health Officer Sundari Mase, in an online briefing Friday afternoon.
She noted 30 to 40 percent of Covid carriers don't show any symptoms.
"Testing ensures that you don't pass Covid on to friends, family and co-workers," urged Mase.
A regular client at the Petaluma site recalled her own experience.
"I got Covid, I don't know where," said Edyth Escorcia, 33, who was surprised when her first Covid test in May was positive.
She had no symptoms, but spent two weeks in a college dorm in quarantine.
Ever since, she makes a point of being tested monthly.
Escorcia works as a cashier and lives in a household with elderly people.
"I don't know if I can get Covid one more time, so this test is what I'm going to do," she explained.
"It's free and it just takes five minutes, I just get off work and come over here to do it."
Robust testing also provides insight into Covid's spread in a community and helps the CDC detect mutations, but only if sufficient tests are done.
"Our hospitals are having the same issue, Kaiser's testing is down about 50 percent," said Sonoma County Supervisor David Rabbitt.
"Their members want a vaccine, not necessarily a swab in their nose."
Rabbitt notes there is an economic cost when testing plunges.
California's re-opening criteria hinges on test data as counties must meet certain benchmarks.
With too few tests, that becomes more difficult.
"We need to make sure that in order to get things open here in Sonoma County and the Bay Area, you need to concentrate on testing as well as getting that vaccine appointment," said Rabbitt.
Most test sites saw business wane after the winter holidays.
"There are not as many sick people anymore," said nurse Richard Solis, administrator of the Petaluma operation.
His site has the capacity to do 330 tests per day.
Lately, there have been days with fewer than 100 tests administered.
Solis says it's usually people who need a test for work or travel, or someone who is considering more activity after months staying home.
"They may not have exposure but they want to make sure they're okay," said Solis.
"Since the start, the oldest person we've tested is 94, the youngest was one year old."
Friday, Solis was impressed by a family of five, parents and three children who came in for testing.
"None of them were ill, but they wanted to contribute to the numbers of Petaluma to show that it's safer."
Testing now, compared to the beginning, is more streamlined and less anxious, with results arriving more reliably.
Jann doesn't expect to halt his weekly tests in the foreseeable future.
"I have a very clean nose," he joked.
He finds it no mystery where everyone else went.
"The vaccination overwhelms people so they don't think about testing anymore, they're just waiting for their shot."
Debora Villalon is a reporter for KTVU. Email Debora at firstname.lastname@example.org and follow her on Twitter @DeboraKTVU.