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Comment by remarkEon | Hacker News Reader

Is there a test for long covid?

Think of AIDS before the immune system dysfunction was found. That's where we are with Long Covid. One cause, a myriad of apparently unrelated effects--that's not how biology tends to work. Rather, there's something deeper we haven't found. And we certainly can't test for what we haven't found.

This is nothing like AIDS.

I am not in any way implying the diseases are related!

I'm saying that it's "like" AIDS in that we are seeing only the top layer, we don't understand what connects them. With AIDS we in time found a common failure in the immune system that by itself didn't produce symptoms, just enabled other failures. And then we found the virus that causes that immune failure.

With Long Covid we have not yet recognized whatever failure they have in common.

And look at how society reacted to AIDS back then. We are doing a lot of the same things with Long Covid.

Yes it is. It's a virus that affects humans. There are. million differences and a million more similarities, saying it's nothing like AIDS without any qualification is just making noise.

There's no such thing as "long COVID" specifically. Any serious viral infection has the potential to cause sequalae in susceptible patients for reasons that are still not well understood. Some of those are detectible in lab tests to an extent but there's no single clear diagnostic test.

they are pretty well understood now with growing evidence of viral persistence in the gut and immune cells, and immune dysfunction causing autoantibodies.

they are also distinct from other conditions like ME/CFS or other sequelae although they may share overlapping symptoms. A lot of research is going into different PAIS post acute infection syndromes

Isnt CFS notoriously post-viral?

evidence says yes, but bacteria and other antigens are being studied. ME/CFS shows antigen persistence like long covid has clearly shown.

https://www.nature.com/articles/s41467-024-45107-3

It's long as in persistent viral colonization, often in immune privileged areas where the virus can hide from the immune system.

One theory is that the immune system doesn't always produce a strong enough antibody response to flush the virus from all these areas but the truth is that's likely only a subset of total cases.

Interesting, then I guess the obvious next question is … is there a test for being a susceptible patient? We’ve been talking about long COVID for years now. Surely there’s some commonalities amongst the people who suffer from it.

not quite. A grab bag of biomarkers being validated in research labs across the USA though

Nothing you can order from your doctor yet but plenty of abnormal findings in almost every aspect of the body. As far as I know none of the findings yet is found in every sufferer, a combination can often get to ~95% but its very heterogenous and that has made it very hard to come up with a single test.

Wouldn’t this be completely expected though?

A sizable percentage of autoimmune cases of well accepted autoimmune diseases (rheumatoid arthritis, celiac, etc etc etc ) are completely seronegative despite glaringly obvious clinical signs: eg peeing skin, deformed joints etc etc - all blood work perfectly normal. Happens all the time.

Why would we expect anything different here?

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