Dropping Antibody Levels

[Shmulie]

How long does it take to get results for the LabCorp test

[Dan]

How long does it take to get results for the LabCorp test

For the quant test? A couple days.

[Shmulie]

For the quant test? A couple days.

I got the labcorp test done on Friday afternoon and just got the results
apparently I have >250.00, no idea if that's high or not but I think >80 is considered positive

For reference I tested positive for Covid about a week after purim 2020, so this is after a year

[Dan]

I got the labcorp test done on Friday afternoon and just got the results
apparently I have >250.00, no idea if that's high or not but I think >80 is considered positive

Greater than 0.8 is positive.
Greater than 250 is off the charts high.

I had 192.6 in January, some 11 months after I had COVID. I'm pretty sure I'd test at greater than 250 now after bring vaccinated.

[Shmulie]

Greater than 0.8 is positive.
Greater than 250 is off the charts high.

I had 192.6 in January, some 11 months after I had COVID. I'm pretty sure I'd test at greater than 250 now after bring vaccinated.

You're right I didn't notice the "."

[Lurker]

A relative got Covid in Mar/Apr 2020. Antibodies test in Mar 21 came back at 279. Antibodies test 3.5 months later came back at 376. AFAIK, it's the same test. Has anyone seen this happen before? Any links that would explain how this could happen?

[Moshe123]

A relative got Covid in Mar/Apr 2020. Antibodies test in Mar 21 came back at 279. Antibodies test 3.5 months later came back at 376. AFAIK, it's the same test. Has anyone seen this happen before? Any links that would explain how this could happen?

Exposure?

[Lurker]

Exposure?

It's a possible theory. I'm looking for any data to support it. Or any data at all, really.

[Dan]

Exposure?

Solid theory.

[Lurker]

Solid theory.

Something @ExGingi has been talking about for a long time now. I'd be very interested to see if anyone is collecting data on this. May bring exposure parties back en vogue (a la chickenpox parties).

[Dan]

Something @ExGingi has been talking about for a long time now. I'd be very interested to see if anyone is collecting data on this. May bring exposure parties back en vogue (a la chickenpox parties).

@biobook

[biobook]

@biobook

The first thing that comes to mind is that a change in antibody tests from 279 to 376 is not necessarily a significant increase.  What you'd want to know is how much variability is there in antibody levels in general.  For example, if antibodies tend to be higher in the morning than in the afternoon, then you could find a seeming "increase" in antibodies by measuring in the afternoon the first time and then in the morning on the second test, 3 months later.  Doesn't mean antibodies are getting higher, just that you've looked at a different point in the cycling levels. 

I don't know how antibodies normally cycle, but I do remember posting something along these lines a while back, in response to something.  Maybe @TimT can find it?  I vaguely remember a graph showing several individuals and measurements of their antibody levels at different times, and it was not a straight line. 

The second thought that comes to mind is that it does take a while for maximal antibody response to develop after an infection, so if the first test was soon after getting sick, then the second test might simply be showing the natural continuation of that antibody response.  Again, this is a vague memory, but I think I had posted something about this, that it took some time to develop.  Can't remember if it was a few weeks, or a few months.  Maybe @TimT can find that too?

[AsherO]

Something @ExGingi has been talking about for a long time now. I'd be very interested to see if anyone is collecting data on this. May bring exposure parties back en vogue (a la chickenpox parties).

Can exposure parties for people with antibodies lead to new mutations? There are known/extant mutations that evade antibodies, fortunately they haven't been significantly more transmissible. A variant that's as transmissible as Delta combined with mutations that evade antibodies would be catastrophic, even in vaccinated societies.

[etech0]

I did not have (enough to be considered positive) antibodies at 2 months, but did at 4. Anecdotal, yes.

[Lurker]

The first point is interesting. I have to find out more about the timing. The second point is actually why I'm so curious. In this particular case, the first test was about one year post infection, so well after the time frame I thought it took to build up a full antibody response, and the second test was 15 months post infection. While I wouldn't be surprised if the levels stayed the same, but I'd expect any change to show a decrease, not an increase, that long post infection.

[Lurker]

Can exposure parties for people with antibodies lead to new mutations? There are known/extant mutations that evade antibodies, fortunately they haven't been significantly more transmissible. A variant that's as transmissible as Delta combined with mutations that evade antibodies would be catastrophic, even in vaccinated societies.

IINM, variants evading antibodies is far from an exact science. I believe the only data we may have is that some variants are more likely to evade antibodies from other strains, but I haven't seen any numbers to show how common it is. There are probably a number of risks for exposure parties, but it may be an alternative for people with antibodies  who are wary of the vaccines, if the risks are found to be low enough.

[TimT]

The first thing that comes to mind is that a change in antibody tests from 279 to 376 is not necessarily a significant increase.  What you'd want to know is how much variability is there in antibody levels in general.  For example, if antibodies tend to be higher in the morning than in the afternoon, then you could find a seeming "increase" in antibodies by measuring in the afternoon the first time and then in the morning on the second test, 3 months later.  Doesn't mean antibodies are getting higher, just that you've looked at a different point in the cycling levels. 

I don't know how antibodies normally cycle, but I do remember posting something along these lines a while back, in response to something.  Maybe @TimT can find it?  I vaguely remember a graph showing several individuals and measurements of their antibody levels at different times, and it was not a straight line. 

The second thought that comes to mind is that it does take a while for maximal antibody response to develop after an infection, so if the first test was soon after getting sick, then the second test might simply be showing the natural continuation of that antibody response.  Again, this is a vague memory, but I think I had posted something about this, that it took some time to develop.  Can't remember if it was a few weeks, or a few months.  Maybe @TimT can find that too?

Referring to this one ?

Here's a partial answer. Quebec researchers measured antibody levels in recovered covid patient who donated convalescent plasma repeatedly. Each line on the graph is another person.  Although antibodies decreased in general over this time period, you can see it fluctuates, and sometimes one measurement is actually higher than the previous one in that person.

https://ashpublications.org/blood/article/doi/10.1182/blood.2020008367/463996/Waning-of-SARS-CoV-2-RBD-antibodies-in
The authors ask whether the repeated donations might actually be responsible for the decline in antibodies. When @Dan suggested this a month ago, I answered that I thought it unlikely based on theoretical issues. The authors apparently did consider it possible, but also concluded that it's unlikely, based on their results here. Their reasoning was that if donating antibodies depleted the supply, then antibody levels should drop more rapidly in those who donated more times, but there was no such correlation.

[AsherO]

IINM, variants evading antibodies is far from an exact science. I believe the only data we may have is that some variants are more likely to evade antibodies from other strains, but I haven't seen any numbers to show how common it is. There are probably a number of risks for exposure parties, but it may be an alternative for people with antibodies  who are wary of the vaccines, if the risks are found to be low enough.

Perhaps not an exact science, but certainly a scientific fact.

[Lurker]

Perhaps not an exact science, but certainly a scientific fact.

Definitely a fact that it happens. I'd like to see data that shows how likely it is to happen.

[AsherO]

Definitely a fact that it happens. I'd like to see data that shows how likely it is to happen.

Not sure how that can be ascertained. Do you mean comparing patient outcomes with/without mutations when all other conditions are equal?

Hard to do, because when these mutations are in the present strain, they present in everyone infected in that particular population. Also, you'd have to sequence all test subjects in the population, which is costly.