In this time of viral and social pandemics, trying to dig for answers is, well, very trying. Recently, there have been three curious tales involving testing for COVID-19 virus.
To review, there are tests with differing techniques from different companies designed to detect the viral presence by its genetic material (antigen tests). And there are tests with differing methods from differing companies to find antibodies that hosts produce to combat the viruses.
Stories about results range as widely as the types of test used — and when testing was done in the course of disease.
The first story is a report of an occurrence of the virus on a cruise ship this spring. It may be the premier example of the rate of asymptomatic infection in a closed environment.
A brief report in the British Journal Thorax entitled “COVID-19: in the steps of Ernest Shakleton” recounted the testing of the 217 crew and passengers on a three-week trip that was supposed to follow the path of a 1915-1917 British explorer from Argentina to the South Pole and back.
The passengers were mostly Australian and New Zealanders. Two of the report’s authors/doctors were passengers and the third the expedition physician. The ship left mid-March when Argentina had recorded 45 cases of COVID-19. By March 31, the number had ballooned to 820 cases.
When the first person aboard developed a fever, everyone was quarantined and tested for antigen. Of the 217 people on the ship, 128 tested positive for the virus, only 24 (19%) had symptoms, eight (6.2%) required medical evacuation, four (3.1%) were intubated and ventilated, and, sadly, one (.8%) died.
The primary observation is that 81% of positives had no reportable symptoms. More curiously, there were 10 instances where two passengers sharing a cabin recorded positive and negative results. Some rapid antibody testing kits were delivered along the way and performed on six passengers and crew who initial fevers. All were negative on day 14.
The conclusions they had were:
81% of infections were asymptomatic, meaning the prevalence, on cruise ships, may be significantly underestimated.
Rapid antibody testing in the acute phase is unreliable.
There could be a significant false-negative rate with antigen testing.
The Abbott labs rapid test method was an initial one used many places, and has been found to have a rate of false negative results. This has been used at the White House. I’m not sure what method is now used.
The second tale is about a 66-year-old San Francisco doctor, head of the clinical services for primary care for University of California San Francisco. An article from San Francisco Chronicle states she had seen patients at a university urgent care clinic on Feb. 25 and March 3 with the now classic fever and cough.
Despite wearing masks, she began to lose here sense of taste and smell and “smell a forest fire,” which can accompany loss of smell. Her first nasal test was negative, but she became isolated at home with her husband March 6, when she started to feel fever, chills and coughs, and had difficulty breathing.
Her husband also developed symptoms on March 11, and both were very sick. He tested negative for COVID but positive for another upper respiratory virus, human metapneumovirus, HMPV.
On March 15, she again tested negative for COVID but positive for HMPV. Her symptoms waned after a course of cortisone for inflammation, but recurred on March 25. On March 26 she finallyt tested positive for COVID, a strange small victory. Her testing was still positive as of May 28. A UCSF infectious disease specialist postulated the viral RNA was present but not likely infective. Her husband never tested positive.
The third testing tale came via Reuters medical News, May 28, from Hunan Normal University in Changsa, China. (What are sick people doing at a normal university?)
After two previously hospitalized patients were readmitted with symptoms and tested positive for COVID, recultures were done on 58 recovered patients with initial positive tests.
Five had positive nasopharygeal swabs, and six had positive anal swabs. One had both positive. None had symptoms. One patient had viral shedding for 56 days after first symptoms. The article did not discuss any antibody test results. As a joke someone posted on Facebook a makeshift sign at a virus testing site, “Covid testing in rear.” Apparently it was true here.
Dr. Wu of Hunan Normal University said, “ After persistent negative RNA test results over four times, some patients retested positive for the viral nucleic acid, RNA. The virus is very cunning.”
What an understatement. The last reading I saw said there were 14 known different mutations infecting humans. We still are adapting to it, and it to us.
We have a lot to learn. The tales told here tell us we have to keep learning and accepting what we learn, except if it is inhumanity or injustice. Then we must learn to change it.
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