Positive Tests for COVID-19 Flat-line as Overall Test Numbers Drop Significantly, Also

COVID-19 testing in the Humboldt County Public Health Laboratory. [IPhoto from the Humboldt County Department of Health and Human Services]

Humboldt County Public Health announced yesterday that there had now been six consecutive days without a positive COVID-19 case — a streak that began somewhat abruptly just days after the local caseload more than doubled over the course of a week. It’s a remarkable change coming just as many were bracing for local numbers to continue to rocket upward.

It’s hard to figure out what to make of the change, as it comes just after Humboldt County ratcheted up social distancing recommendations — modifying a shelter-in-place order to make it more stringent and officially asking residents to wear facial coverings when leaving home — but also as testing numbers dipped significantly.

The week of March 30, when Humboldt saw its caseload double, 536 residents — or 76.6 a day — were tested for COVID-19. The following week, when six cases were announced and the no-new-case streak began, just 319 residents were tested, or 45.6 a day. That’s a 40 percent drop-off, much of it due to a sharp decline in tests results coming from the two out of area corporate labs that processes local samples.

After testing an average of 38.66 patients per day over a nine-day stretch, the labs have returned just 4.5 test results a day over the last six.

At a media availability event last week, Humboldt County Public Health Officer Teresa Frankovich said she, too, had noticed the significant drop-off in test results coming from out of the area and wasn’t sure whether it was the result of fewer residents being tested or a backlog at the testing facilities.

Humboldt County Public Health Laboratory staff analyzing a COVID-19 test. [Photo from the Humboldt County Department of Health and Human Services]

The Times-Standard’s Sonia Waraich reported April 10 that Open Door Community Health Centers CEO Tory Starr said that one of the private labs — LabCorp — had “totally gotten backed up.” But a company spokesperson also told Waraich that it had ramped up testing capacity by about 40,000 tests per day. While Humboldt County has generally gotten results back from the private labs within three or four days of sending a sample, other areas have complained of delays of seven to 10 days. All of this points to a possible backlog of test results set to hit Humboldt County in a bunch. If that’s the case, we should begin to see it in the coming days.

But Frankovich also posited that maybe healthcare providers are just testing fewer people. Humboldt County is heading out of the traditional flu season, she said, so there are fewer people with respiratory illness symptoms that can present like COVID-19 and trigger a test. There may be some evidence to support this, as the local public health laboratory’s testing rate also declined the week of April 6, dipping about 20 percent from its high of 253 tests run the week prior. But that theory would also suggest, as Frankovich mentioned, that people coming to their providers with respiratory illness “may be increasingly likely to test positive for COVID.”

But Humboldt County is not seeing a higher percentage of its daily tests coming back positive. It’s been the opposite. As of yesterday, 1,418 Humboldt County residents had been tested for COVID-19, with 50 returning positive, or an average of roughly one positive for every 28 tests. Humboldt County has now seen 229 samples pass without a positive case. That’s unquestionably a small sample size and could prove an anomaly. Only more testing will tell.

Of course, testing availability remains incredibly limited. While Humboldt County has tested significantly more people per capita than other California counties — as of April 9, it was testing at more than double the rate of Los Angeles County, for example — there still aren’t enough supplies to test everyone who is symptomatic, much less to conduct more proactive surveillance testing.

[Photo from the Humboldt County Department of Health and Human Services]

That’s because the supply chain remains under incredible strain, with everything from testing swabs to reagents in short supply and high demand. This coupled with the fact that the local Public Health lab can turn around test results days faster than its corporate counterparts has left Public Health to be very selective about which patients get tested locally and which samples get sent out of the area. The last thing Public Health wants is to run out of tests due to supply chain issues and see a critically ill local patient — or someone like a healthcare worker, with a great capacity to spread the illness — whom it can’t quickly test. So the department is, to a degree, conserving tests.

“We are constantly in a position of working to acquire more kits because we’re using them on an ongoing basis,” Frankovich said.

As of this writing, Public Health is reporting that it has capacity on hand for 600 tests, but since March 21 that number has fluctuated from a low of 398 to a high of 750.

Frankovich said last week that providers are still following the Centers for Disease Control recommendations regarding who gets tested: people who are severely symptomatic or symptomatic and in a high risk group (like over the age of 65 or with an underlying health issue) or have come into contact with a confirmed case. People who are mildly symptomatic are still being told to stay home, isolate and monitor their symptoms, as there is still no cure or treatment for the disease, and someone with a confirmed mild case would be told to do the same.

Of Humboldt County’s 50 confirmed cases, 23 were traced back to contact with another known case and 20 others were related to international travel. But the seven others are believed to have stemmed from community transmission, meaning the source is unknown but believed to have been from someone or somewhere in Humboldt County. This would indicate the virus is continuing to spread through the community because Public Health hasn’t been able to conduct contact investigations, intervene and order people to quarantine. Some studies have also shown that 25 percent of people who get the virus never become symptomatic, meaning they can spread it without ever knowing they had it.

Frankovich said last week, toward the beginning of the no-new-case streak, that Humboldt County was nowhere near its peak of COVID-19 cases. Pressed a couple days later to elaborate on the county’s modeling projections, she said there are too many variables to have any faith in them but that the state may be releasing county-by-county projections soon. But with just roughly 1 percent of Humboldt County residents having been tested — and remember, we’re ahead of almost the entirety of the state with that number — it will be hard to know how much stock to put in those models.

As other countries have shown, widespread testing has been a crucial component of getting a handle on the virus. In that sense, we’re moving in the wrong direction.

“The more we can test the more we can detect,” Frankovich said last week. “But I can tell you because we’ve identified community transmission cases that we do have COVID circulating in our community.”

Preparing COVID-19 Test Kits at HSU. [Photo courtesy Humboldt State University]