Covid19 tests picking up traces of old innactive virus

[Amity Island]

The main test used to diagnose coronavirus is so sensitive it could be picking up fragments of dead virus from old infections, scientists say.

Most people are infectious only for about a week, but could test positive weeks afterwards.

Researchers say this could be leading to an over-estimate of the current scale of the pandemic.

But some experts say it is uncertain how a reliable test can be produced that doesn't risk missing cases.

Prof Carl Heneghan, one of the study's authors, said instead of giving a "yes/no" result based on whether any virus is detected, tests should have a cut-off point so that very small amounts of virus do not trigger a positive result.

He believes the detection of traces of old virus could partly explain why the number of cases is rising while hospital admissions remain stable.

Coronavirus: Tests 'could be picking up dead virus'

Scientists say a positive coronavirus result does not guarantee that someone is infectious.

www.bbc.co.uk

 

[Docb]

Odd in that I have always assumed that all the test indicated that virus was in the sample. It cannot tell you whether the person is infectious or not and so you finish up with a default position where any positive test is assumed to be from an infectious person even though they might have passed the infectious stage but still carry the virus. The things mentioned in the article then follow logically from assuming that default.

I strongly suspect that infections are rising but hospitalisations are stable because the infection is spreading amongst those least vulnerable to the disease. These days the more vulnerable are better informed and better protected and are simply managing the risk and not catching it. It would be nice to see what the age profile of positive cases is to see if this idea is sensible.

 

[trophywench]

Ah, well doc, thing on the TV news last night saying it's because such a lot of the positive tests and hospital admissions are in the 18 - 30 age group they are more than worried.

 

[Bruce Stephens]

Christina Pagel is more skeptical. (Basically, how could so many currently asymptomatic, previously infected people, be getting tested to make any difference, given that we don't really test asymptomatic people much?)

Thread by @chrischirp: THREAD: I have a big problem with how this @BBCNews article has been presented bbc.co.uk/news/health-54… Firstly, the academic paper behind…

Thread by @chrischirp: THREAD: I have a big problem with how this @BBCNews article has been presented bbc.co.uk/news/health-54… Firstly, the paper behind it (a review of best available evidence) is absolutely right to point out that PCR tests for COVID a…

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