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Comment by thoraway1010 | Hacker News Reader

The results I got had a big FDA warning that positive results may be a result of other infections (ie, that the tests are not specific to covid).

I feel like the WHO (body may not produce antibodies as part of beating covid, antibodies have not been shown to confer any immunity) and now the FDA may be talking about true but theoretical issues.

What is the REAL rate, in the USA, of folks who have for example MERS antibodies that will trigger a false positive in this type of test. Ie, do these tests really come back positive for MERS antibodies and how likely am I to have had MERS but not covid so that I get that false positive?

Given the FDA warning (which was the biggest thing on my results) I'm guessing 30%+ of positives are a result of these situations? But interested in actual data

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MERS and SARS are not a huge concern (they never achieved wide circulation), but coronaviruses make up ~40% of what we know as the common cold.

That said, if the false positive rate were that high, the specificity of the test would be low.

These tests are not FDA approved, they're being allowed under emergency use authorization. They're not subject to the same rigger as tests normally allowed on the market and the manufacturer's specifications may be overstated.

"They're not subject to the same rigger as tests normally allowed on the market and the manufacturer's specifications may be overstated."

"rigor"

Also, the error bars on these may be wider than is usual for an approved test, but they are just as likely to be understated as overstated.

"rigour" :)

> ...but coronaviruses make up ~40% of what we know as the common cold.

Up to 20%, and I've seen numbers as low as 15% [1].

[1] https://www.webmd.com/cold-and-flu/cold-guide/common_cold_ca...

Although I think the WHO has been way too cryptic talking about the issues surrounding antibodies and immunity, I think the real questions are really around degrees of immunity.

It might be that 80% of people get antibodies and immunity, but 20% don't. Or some people get antibodies but it doesn't prevent them from being a carrier. Or the immunity is only partial, etc. And then there's the ADE stuff which is theoretical but scary.

> I feel like the WHO (body may not produce antibodies as part of beating covid,

FTR, this assertion has been proven to be false (the other needs further investigation)[1]. Antibodies (IgM and IgG) are produced during the infection and peak afterwards.

[1] https://www.nature.com/articles/s41591-020-0897-1

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