The negative follow-up tests of Sitka’s first confirmed coronavirus case don’t invalidate the initial result, says public health nurse Denise Ewing, who assists the state Section of Epidemiology with “contact tracing” for patients who have positive tests.  “But they’re continuing to look at it,” she said. In this image, SEARHC personnel test a colleague for COVID-19 at the employee screening tent behind the hospital on April 28, 2020. (KCAW photo/Berett Wilber)

Sitka’s first reported coronavirus remains a confirmed positive case, despite the fact that the patient has since tested negative.

The state Section of Epidemiology and Sitka Unified Command issued a news release Thursday afternoon (4-30-20) reminding residents that the case remains a positive case, and to continue to observe all local and state health mandates.

 

 

From the very first news conference on the issue (on Monday, April 27), it’s been clear that Sitka’s first confirmed case of coronavirus was unusual: The patient, a resident of Sitka Long-Term care, had been living in lockdown for six weeks, and had never exhibited any symptoms of the disease.

When he was isolated at the Mt. Edgecumbe Medical Center (on April 25) the patient was given a rapid test, that came back negative. So did a subsequent — and far more reliable lab test.

But public health nurse Denise Ewing, who performed the contact tracing on the case for the state Section of Epidemiology, says the subsequent negative tests don’t mean that the original one was a false positive.

“Because he did test positive for his first test,” said Ewing, “it remains a positive.”

Ewing says Epidemiology has ruled out many of the causes of a false positive, such as cross-contamination in the lab. So the positive result stands. And there are just as many reasons why a patient could test positive, and shortly thereafter test negative.

“Without conjecture, there is not a clear reason as to why,” Ewing said. “That’s why they’re continuing to still look at it.”

One possibility is that this patient was tested near the end of the period when he was shedding virus. Although the results were received and publicly announced on April 25, specimens were collected from the patient — and all the other residents of Sitka Long-Term Care — six days earlier.

But again, Ewing says that “not many of us want to go down that trail, because we get in trouble when we do.” Epidemiology is not about guesswork.

“We don’t know at what point he was on in his journey with covid, because he was asymptomatic,” said Ewing. “So there are so many avenues, that’s why Epi says ‘If it was a positive, it’s a positive.’”

Ewing says that antibody testing may eventually clear up some of the unknowns around this patient, but she doesn’t know if that will happen in this case.

The Sitka Unified Command, meanwhile, doesn’t want Sitkans to relax their guard. They’d like everyone to continue to adhere to all local and state health mandates, observe social distancing guidelines, and to continue good hygiene practices.