RobertL18C wrote:
Is it correct that the experience in Africa, and specially South Africa is very different to the rest of the world? Lower mortality despite high urban concentrations and higher poverty levels.
My – totally unscientific – explanation is the same as for the very low rates in SE Asia. A much, much more vigorous immune system. Living in Africa and to a lesser extent SE Asia you get exposed to pretty much anything Mother Nature can throw at you. OTOH, in our super-sanitized ‘western’ world, we avoid germs at almost all cost – until the cost of that avoidance becomes death.
dublinpilot wrote:
Certainly in Ireland we’ve been testing everyone with symptoms for long before the current spike. Yet the outcomes (increased positive cases but reduced death rate) seems to be largely universal.
Yes, the increased testing does not explain the increase in diagnosed cases day-on-day over the recent weeks. It does explain the much higher incidence of cases vs deaths compared to, say, March or April.
Interesting hypothesis – as the common cold corona virus E229 and other coronaviridae start circulating more, the test positive rate goes up…
As a casual observation, having traveled to Europe and the US the last few weeks, Americans are generally taking social distancing and mask wearing more seriously than Europeans.
I was pretty shocked to discover that much of the disdain for the US wrt precautions and prevention was inverted in reality.
Hardly anyone (including UK, Germany, France and Austria) kept their distance or properly wore a mask in public, with the exception of grocery stores, where everyone did.
In the US, everyone social distances everywhere and it is very common to see masks in most public places.
It isn’t a mystery to me that the cases in Europe are piling up…
Also, I don’t get why this is such an issue.
The virus is going nowhere, and it isn’t that lethal for the healthy crowd.
Also agree with you Peter, watching people avoid contact and be really freaked out, yet gladly handle money all day is a complete laugh to me.
hmng wrote:
What do people think the false positive rate for the PCR tests can be?
False positives for a PCR test are very unlikely. Certainly well below 1%. It is known that the common swab test can lead to a high number of false negatives however, in the magnitude of 5 to 15% I reckon.
I would like a source for that @Medewok
I posted the link to some German lab quality control study here in April or so, and false positives were above 1 % IIRC and they praised that as very good. Also those were standardized test samples sent to multiple labs, so I think they didn’t contain other coronavirus traces.
Here an article from JAMA, a very respected medical journal.
They wrote:
False-negative results mainly occurred due to inappropriate timing of sample collection in relation to illness onset and deficiency in sampling technique, especially of nasopharyngeal swabs. Specificity of most of the RT-PCR tests is 100% because the primer design is specific to the genome sequence of SARS-CoV-2. Occasional false-positive results may occur due to technical errors and reagent contamination.
MedEwok wrote:
False positives for a PCR test are very unlikely.
It was reported, that PCR tests are very reliable, but what they have not done, because they don’t the answer, is to calculate a reliable threshold that says that this person has an active infection as opposed to a residual amount of the virus after the infection has gone, say several weeks or months ago.
Medework
I’ve only relied on google translate for the information on this so perhaps the german reads it differently. But this suggests false positives are presently a problem does it not?
https://www.aerzteblatt.de/archiv/213794/COVID-19-Krise-Falsch-Positiv-Rate-als-Problem
@MedEwok so you don’t believe this study?
https://corona-transition.org/sars-cov-2-tests-haben-hohe-fehlerraten
Any particular reason why you think it might be wrong?
