Convalescent plasma useless and high titer IgG non-protective?

[LADoc00]

I heard both these today. I don't think I need to explain to this crowd the utter gravity of these new revelations.

If this is true, which I suspect it is, then the "no vaccine possible" scenario is very real.

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[Thr0mbus]

We have had good initial results with convalescent plasma. I think it needs to be used before the vent.

I think there is much merit in this approach, approaches that clean out the cytokines in blood (plasma exchange?) and approaches that inhibit inflammatory response leading to ARDS

 

[Thr0mbus]

I also think there may be merit in trying convalescent plasma from different recovered patients in the same symptomatic patient.

 

[ccous]

If you seroconvert early and have high titer IgG, does this lead to worse outcomes as was demonstrated in SARS 2003?

 

[Atreus21]

The jury is still out on how protective IgG is for COVID. I know a few labs have LDT's and even the big players like Quest, ARUP, etc are only just coming up with serology. Most vendors I have seen just have a qualitative assay. I'm sure we will get a quantitative assay down the road.

Is it protective? No one knows
Is there a certain titer that gives immunity? No one knows

This is all way too early to tell. I have seen some neutralization studies that are promising and there was a study in macaques that showed high levels of IgG with a protective response a month later after injection with the virus. However, will this translate to humans no one knows.

I'm not an expert on this, but I assume we can answer this question with studies that follow patients with high titers.

Many patients with SARS-1 had high IgG levels for years after exposure (but again does that mean immunity?).

Will this act like HIV or HCV where it is a marker of exposure? Or will it act like HBV or measles?

The CDC, NIH, academic labs, etc will hopefully answer these questions in the next few months.

 

[Napoleon1801]

Preliminary results for convalescent plasma have been pretty good for us. Personally very interested in the JHU trial using convalescent plasma for post-exposure prophylaxis.