Positive. Again.
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Disconcerting news. May have been posted here, but if not ...
"SOUTH KOREAN OFFICIALS reported that nearly 100 people thought to be cured of the novel coronavirus have tested positive again.
Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention said during a briefing that the virus may have "reactivated" in the patients rather than them becoming reinfected, Reuters reported.
Health officials in the country said it is unclear how or why this has happened in the 91 patients, but an epidemiological investigation is underway."
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More background.
"SEOUL (Reuters) - South Korean officials on Friday reported 91 patients thought cleared of the new coronavirus had tested positive again.
Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention (KCDC), told a briefing that the virus may have been “reactivated” rather than the patients being re-infected.
South Korean health officials said it remains unclear what is behind the trend, with epidemiological investigations still under way.
The prospect of people being re-infected with the virus is of international concern, as many countries are hoping that infected populations will develop sufficient immunity to prevent a resurgence of the pandemic.
The South Korean figure had risen from 51 such cases on Monday.
Nearly 7,000 South Koreans have been reported as recovered from COVID-19, the disease caused by the new coronavirus.
“The number will only increase, 91 is just the beginning now,” said Kim Woo-joo, professor of infectious diseases at Korea University Guro Hospital.
The KCDC’s Jeong raised the possibility that rather than patients being re-infected, the virus may have been “reactivated”.
Kim also said patients had likely “relapsed” rather than been re-infected.
False test results could also be at fault, other experts said, or remnants of the virus could still be in patients’ systems but not be infectious or of danger to the host or others." -
Okay, so likely not a "re-infection," other factors like testing could be the culprit, and the relative number of relapsed cases remains pretty small. Here's hoping it's not what everyone's worried about.
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@Aqua-Letifer
Agreed. It puts the whole 'cured' concept into question. Getting better may not mean getting over it.It doesn't discuss the whether the second positive indicates the person is infectious again, but one would assume so.
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Good point on the testing question. In this case, it would be a false positive on the first round, and then a true positive in the second. Still worth watching and retesting as needed when a period of time has elapsed, no matter what the first test reult was.
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There has been a lot of talk about false positives and false negatives in the testing process. Frankly, I wish we had a bit better test, period.
Always remember, Operation Valkyrie was an act of sedition.
Warning: I post things that interest me. Read and comment at your own discretion. -
@Jolly said in Positive. Again.:
There has been a lot of talk about false positives and false negatives in the testing process. Frankly, I wish we had a bit better test, period.
Good-Fast-Cheap... Need I go on?
Me/rry/Christmas
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@LuFins-Dad said in Positive. Again.:
@Jolly said in Positive. Again.:
There has been a lot of talk about false positives and false negatives in the testing process. Frankly, I wish we had a bit better test, period.
Good-Fast-Cheap... Need I go on?
George has taught you well, Padawan...
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@Klaus said in Positive. Again.:
Do we have false positive/false negative rates on the test? Maybe this is merely due to false test results.
NO clinical test is accurate 100% of the time. I've heard error rates of 10% on the current COVID tests. 5% is around minimum for many tests, even less for others.
Always remember, Operation Valkyrie was an act of sedition.
Warning: I post things that interest me. Read and comment at your own discretion. -
@Jolly said in Positive. Again.:
@Klaus said in Positive. Again.:
Do we have false positive/false negative rates on the test? Maybe this is merely due to false test results.
NO clinical test is accurate 100% of the time. I've heard error rates of 10% on the current COVID tests. 5% is around minimum for many tests, even less for others.
Jolly, is it evenly spread? In other words, are false positives as common as false negatives? How do you prove a false negative, if a certain amount of time (week) has passed before the re-test?
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@Rainman said in Positive. Again.:
@Jolly said in Positive. Again.:
@Klaus said in Positive. Again.:
Do we have false positive/false negative rates on the test? Maybe this is merely due to false test results.
NO clinical test is accurate 100% of the time. I've heard error rates of 10% on the current COVID tests. 5% is around minimum for many tests, even less for others.
Jolly, is it evenly spread? In other words, are false positives as common as false negatives? How do you prove a false negative, if a certain amount of time (week) has passed before the re-test?
Depends on the methodology of the test and the person running it. Sometimes, you can have an adequate test, but a lousy tester.
An example: Monoclonal antibody tests for pregnancy are ubiquitous. You can buy them for $1/each at the dollar store. A study was done with known specimens comparing everyday folks with lab testing personnel. Average people got the right answer around 80% of the time. The lab people were right about 95% of the time, with their accuracy equaling the stated accuracy of the test.
It's all about technique, specificity and sensitivity. The more sensitive a test, the less specific. The more specific, the less the sensitivity. Sloppy technique equals sloppy results. And any test with a manual component such as pipetting, is more accurate with somebody who has done the test many, many times.
And don't forget, you have to have a good sample, to get a good test.
Another factor...Sometimes the test is collected correctly, done correctlyand reported erroneously. Doesn't happen much anymore because most things are interfaced, but guys have been known to type in the wrong answer.
So errors occur in three phases - pre-analytical, analytical and post-analytical, with the majority of problems usually occurring in the pre-analytical phase( collection and everything before actual testing).
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In the tests I've been involved with designing, for use with the droplet digital pcr instruments I work with, a lot of effort goes into the "no answer" category. If the data does not look good enough to the results algorithm, the algorithm refuses to give an answer.
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@Jolly said in Positive. Again.:
@Klaus said in Positive. Again.:
Do we have false positive/false negative rates on the test? Maybe this is merely due to false test results.
NO clinical test is accurate 100% of the time. I've heard error rates of 10% on the current COVID tests. 5% is around minimum for many tests, even less for others.
If that test would have a 10% false positive rate, then it would be mostly useless, no? From what I understand, the number of tests with positive results is around or below 10%. At a 10% false positive rate, most of those "positive" cases would in fact be negative.
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@Klaus said in Positive. Again.:
@Jolly said in Positive. Again.:
@Klaus said in Positive. Again.:
Do we have false positive/false negative rates on the test? Maybe this is merely due to false test results.
NO clinical test is accurate 100% of the time. I've heard error rates of 10% on the current COVID tests. 5% is around minimum for many tests, even less for others.
If that test would have a 10% false positive rate, then it would be mostly useless, no? From what I understand, the number of tests with positive results is around or below 10%. At a 10% false positive rate, most of those "positive" cases would in fact be negative.
I don't know if that is the actual number, I'm working off of gossip, hearsay and the news media. But you would be much better off with false positives than false negatives.
