Author Topic: Dropping Antibody Levels  (Read 16430 times)

Offline meme

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Re: Dropping Antibody Levels
« Reply #210 on: October 20, 2020, 07:20:27 PM »
I took their antibody test yesterday and got results within 3 hours. Negative for antibodies (I tested .10, where anything .99 or less is negative).

The result page didnít say which test it was, it was called ďCOVID-19 Total AntibodyĒ.

ETA:

The results included the following two links which imply itís the Roche test. The PDFs in the links donít seem to provide information on how to interpret the test result numbers:

Providers: https://www.fda.gov/media/137603/download
Recipients: https://www.fda.gov/media/137604/download
Where did you take this test?

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Re: Dropping Antibody Levels
« Reply #211 on: October 20, 2020, 07:23:02 PM »
Where did you take this test?

Kings County hospitalís walk-in COVID testing. Itís in tents outside the D building (I think thatís what itís called).

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Re: Dropping Antibody Levels
« Reply #212 on: October 20, 2020, 10:58:43 PM »
Labcor  @ walgreens just says postive or negative.
^^^

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Re: Dropping Antibody Levels
« Reply #213 on: October 20, 2020, 11:03:24 PM »
Labcor  @ walgreens just says postive or negative.
Which test was it?
Save your time, I don't answer PM. Post it in the forum and a dedicated DDF'er will get back to you as soon as possible.

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Re: Dropping Antibody Levels
« Reply #214 on: October 21, 2020, 01:23:28 AM »
Sure, but it would allow you to track the movement of your own antibodies over time.
So it could be fun, like some people track their weight over time, or blood pressure, or fitbit activity.   But @skyguy918 wondered "if there's some number that translates to an immunity threshold" and we seem to be far from knowing that.  Two reasons: We don't know what level of antibodies allows re-infection (or if cases like that Nevada one are rare flukes).  And we do know that even if antibodies become undetectable, there may well be memory B cells that are able to quickly ramp up antibody production if we're reinfected (at least this is true for some other diseases), as well as T cells that may prevent a second illness. 

I found a couple of clinical trials that are trying to figure out this relationship between antibody level and immunity.

https://clinicaltrials.gov/ct2/show/NCT04540484?id=NCT04540484&draw=2&rank=1
COVID-19 IgG Formation in Physicians at ALGH and Their Household Members
"...To date, there have been no studies confirming that IgG antibody formation confers immunity, but studies are ongoing. Furthermore, data is lacking showing conclusive persistence of (possibly protective) antibodies over time." So they're studying physicians at a particular hospital in Illinois, where there are a lot of covid patients treated.  The doctors' antibody level will be measured every 3 months, and they'll also be able to relate this to any covid (re)infections that develop in the doctors.  That study is expected to take a year.

https://clinicaltrials.gov/ct2/show/NCT04411147?id=NCT04411147&draw=2&rank=1
A Longitudinal Study of COVID-19 Sequelae and Immunity
"Objective: To learn about any long-term medical problems that people who have recovered from COVID-19 might have, and whether they develop an immune response to SARS-CoV-2 that provides protection against reinfection."  They'll assay antibody levels every 6 months, for 3 years.   This one is recruiting 900 participants, and anyone who meets the criteria is welcome to apply.  You get free antibody tests!  I don't know if they reimburse you for transportation costs to the NIH lab in Bethesda MD, but you can use points and get an unusual TR out of it! 

Offline ExGingi

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Re: Dropping Antibody Levels
« Reply #215 on: October 21, 2020, 07:12:59 AM »
DW just got her test results from Hadassah Medical in EY. Her IgG number shows about 2x what her most recent test taken in the US showed. (Same scale. Over 15.0 considered positive).
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Re: Dropping Antibody Levels
« Reply #216 on: October 21, 2020, 09:44:11 AM »
^^^

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Re: Dropping Antibody Levels
« Reply #217 on: October 21, 2020, 10:22:43 AM »
So it could be fun, like some people track their weight over time, or blood pressure, or fitbit activity.   But @skyguy918 wondered "if there's some number that translates to an immunity threshold" and we seem to be far from knowing that.  Two reasons: We don't know what level of antibodies allows re-infection (or if cases like that Nevada one are rare flukes).  And we do know that even if antibodies become undetectable, there may well be memory B cells that are able to quickly ramp up antibody production if we're reinfected (at least this is true for some other diseases), as well as T cells that may prevent a second illness. 
Yeah, so I'm not wondering about whether an actual threshold has been scientifically established. The facts on the ground are that some (not the CDC, or most government entities in the US) are assuming that there is some threshold and there are numbers being used as a threshold for each antibody test. Like Israel for example:
https://www.dansdeals.com/more/dans-commentary/news-roundup/israel-travel-news-roundup-flight-sales-open-antibody-tests-accepted-el-al-status-extension-uae-bilateral-agreement-etihad-israel-site-new-era-inshallah/

Another example: The most vocal KGH doctor throughout the pandemic (as in vocal about the need to take it seriously, the need to shut things down, etc.) holds strongly of antibody immunity, to the point that he doesn't where he (I assume being positive for antibodies) doesn't war a mask most of the time despite his practice probably being one of the primary testing sites for the frum community. When I tested positive and and he was telling me to quarantine my family, I asked about my wife (who had just retaken antibody test at his practice a week earlier) and he said with a recent positive immunity level antibody test she doesn't have to quarantine. I don't know which test he uses or what his threshold is, but I know my family's numbers for the Roche test that NYC Health and Hospitals is currently administering, hence my question. Realistically it's not changing my behavior, but I am curious.

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Re: Dropping Antibody Levels
« Reply #218 on: October 21, 2020, 07:53:08 PM »
Yeah, so I'm not wondering about whether an actual threshold has been scientifically established. The facts on the ground are that some (not the CDC, or most government entities in the US) are assuming that there is some threshold and there are numbers being used as a threshold for each antibody test. Like Israel for example:
https://www.dansdeals.com/more/dans-commentary/news-roundup/israel-travel-news-roundup-flight-sales-open-antibody-tests-accepted-el-al-status-extension-uae-bilateral-agreement-etihad-israel-site-new-era-inshallah/

Another example: The most vocal KGH doctor throughout the pandemic (as in vocal about the need to take it seriously, the need to shut things down, etc.) holds strongly of antibody immunity, to the point that he doesn't where he (I assume being positive for antibodies) doesn't war a mask most of the time despite his practice probably being one of the primary testing sites for the frum community. When I tested positive and and he was telling me to quarantine my family, I asked about my wife (who had just retaken antibody test at his practice a week earlier) and he said with a recent positive immunity level antibody test she doesn't have to quarantine. I don't know which test he uses or what his threshold is, but I know my family's numbers for the Roche test that NYC Health and Hospitals is currently administering, hence my question. Realistically it's not changing my behavior, but I am curious.

Those who study viruses suspect that immunity will be similar to other known coronaviruses, where immunity lasts a year or two.  Some might be reinfected as soon as 2 months (as we've seen one case), while most will probably be immune for 6 months to a year.

The positive antibody test just confirms Yes, you've had covid, either quite recently or a short time ago when you felt sick.  If you want to act based on assumptions, then it makes more sense to base it on time passed since infection, and not on specific antibody numbers, since we don't know how/if those relate to immunity.  I would guess that it was the recency of infection that led the doctor to assume that he and your wife had some immunity.

The Israel Dept of Health refers to numbers used by the companies who developed the test as the threshold for concluding that the test is positive (or borderline).  That's a threshold for measurable antibodies, not a threshold for immunity.

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Re: Dropping Antibody Levels
« Reply #219 on: October 21, 2020, 08:58:31 PM »
Those who study viruses suspect that immunity will be similar to other known coronaviruses, where immunity lasts a year or two.  Some might be reinfected as soon as 2 months (as we've seen one case), while most will probably be immune for 6 months to a year.

The positive antibody test just confirms Yes, you've had covid, either quite recently or a short time ago when you felt sick.  If you want to act based on assumptions, then it makes more sense to base it on time passed since infection, and not on specific antibody numbers, since we don't know how/if those relate to immunity.  I would guess that it was the recency of infection that led the doctor to assume that he and your wife had some immunity.

The Israel Dept of Health refers to numbers used by the companies who developed the test as the threshold for concluding that the test is positive (or borderline).  That's a threshold for measurable antibodies, not a threshold for immunity.
Your assumption (bolded) is incorrect. She was COVID positive sometime between Purim and Pesach. She tested positive for antibodies (Mt Sinai) with a result she was told was relatively a high number. When she tested more recently (probably late Sep) with this local doctor, he told her the number was a little over immunity level (ie implying that there had been a drop).

Re Israel, what use is a positive/negative antibody result if it doesn't imply anything about current state of infection or potential immunity? I don't see how it's useful unless you assume some level of immunity.

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Re: Dropping Antibody Levels
« Reply #220 on: October 22, 2020, 12:20:25 PM »
Your assumption (bolded) is incorrect. She was COVID positive sometime between Purim and Pesach. She tested positive for antibodies (Mt Sinai) with a result she was told was relatively a high number. When she tested more recently (probably late Sep) with this local doctor, he told her the number was a little over immunity level (ie implying that there had been a drop).
Okay, so here's a different assumption  :)  When the doctor said "a little over immunity level" he probably meant "a little over antibody threshold level", that is, a little over the number that is used to conclude that the antibody test is positive.  Nobody knows yet what level of antibody will provide the immunity needed to avoid a second infection. 
Quote
Re Israel, what use is a positive/negative antibody result if it doesn't imply anything about current state of infection or potential immunity? I don't see how it's useful unless you assume some level of immunity.

Israel's goal is to decrease entry of virus into the country, balanced by the economic and social needs to allow travel.  They're not at all interested in any individual's particular level of immunity, nor interested in how this will change over time.  They just want to know, on that day that you're flying, what's the chance that you're bringing in live virus.

A positive antibody test implies that someone PROBABLY has been exposed to coronavirus, and PROBABLY is immune, and so is PROBABLY not carrying live virus now.  There's a lot of uncertainty there, but based on our knowledge of other coronaviruses, let's say we're 95% certain they're not carrying the virus.  So a group of antibody-positive travelers is much less likely to import the virus than a random group of people coming from NY/NJ.  Some infected people probably WILL enter, but hopefully very few.  If Israel is trying to ramp up travel, it makes sense to begin by allowing this group in first, and seeing how it goes.  (Actually, they rescinded permission for this yesterday, I think, not sure why.)

But decisions we make for groups of people - public health - is not always the same as decisions made for individual health. 

If 95% of Ab+ people are immune today (and I totally made up this number), it still means that 5% of Ab+ people are susceptible to infection/reinfection/transmitting the virus to others.  And that 5% will increase over time as immunity weakens. 

As an individual, my goal is to prevent illness to myself and others. The antibody test doesn't give a yes/no answer to immunity.  If I'm Ab+, I wouldn't say "Now, I'm immune, I can spend time with my great grandmother."  Rather, "Now there's a 95% chance I'm immune, and only a 5% chance that if I spend time with my great grandmother, I'll infect her and cause her death."  We need to keep that (still unknown) probability in mind when we make our decisions. 

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Re: Dropping Antibody Levels
« Reply #221 on: October 22, 2020, 12:23:48 PM »
Okay, so here's a different assumption  :)  When the doctor said "a little over immunity level" he probably meant "a little over antibody threshold level", that is, a little over the number that is used to conclude that the antibody test is positive.  Nobody knows yet what level of antibody will provide the immunity needed to avoid a second infection. 
Israel's goal is to decrease entry of virus into the country, balanced by the economic and social needs to allow travel.  They're not at all interested in any individual's particular level of immunity, nor interested in how this will change over time.  They just want to know, on that day that you're flying, what's the chance that you're bringing in live virus.

A positive antibody test implies that someone PROBABLY has been exposed to coronavirus, and PROBABLY is immune, and so is PROBABLY not carrying live virus now.  There's a lot of uncertainty there, but based on our knowledge of other coronaviruses, let's say we're 95% certain they can't carry the virus.  So a group of antibody-positive travelers is much less likely to import the virus than a random group of people coming from NY/NJ.  Some infected people probably WILL enter, but hopefully very few.  If Israel is trying to ramp up travel, it makes sense to begin by allowing this group in first, and seeing how it goes.  (Actually, they rescinded permission for this yesterday, I think, not sure why.)

But decisions we make for groups of people - public health - is not always the same as decisions made for individual health. 

If 95% of Ab+ people are immune today (and I totally made up this number), it still means that 5% of Ab+ people are susceptible to infection/reinfection/transmitting the virus to others.  And that 5% will increase over time as immunity weakens. 

As an individual, my goal is to prevent illness to myself and others. The antibody test doesn't give a yes/no answer to immunity.  If I'm Ab+, I wouldn't say "Now, I'm immune, I can spend time with my great grandmother."  Rather, "Now there's a 95% chance I'm immune, and only a 5% chance that if I spend time with my great grandmother, I'll infect her and cause her death."  We need to keep that (still unknown) probability in mind when we make our decisions.
FTFY
I wonder what people who type "u" instead of "you" do with all their free time.

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Re: Dropping Antibody Levels
« Reply #222 on: October 22, 2020, 12:30:24 PM »
FTFY

The corollary of that fix is that if there is a 5% chance that they are not immune it does not mean a 5% of transmitting. They would still need to become infected. So if someone Ab- has a 10% chance of being infected and able to transmit at a given time (this number is random and likely high) that would mean having a .5% chance of making the grandmother sick.



As an individual, my goal is to prevent illness to myself and others. The antibody test doesn't give a yes/no answer to immunity.  If I'm Ab+, I wouldn't say "Now, I'm immune, I can spend time with my great grandmother."  Rather, "Now there's a 95% chance I'm immune, and only a 5% chance that if I spend time with my great grandmother, I'll infect her and cause her death."  We need to keep that (still unknown) probability in mind when we make our decisions. 
Feelings don't care about your facts

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Re: Dropping Antibody Levels
« Reply #223 on: October 22, 2020, 12:33:14 PM »
DW just got her test results from Hadassah Medical in EY. Her IgG number shows about 2x what her most recent test taken in the US showed. (Same scale. Over 15.0 considered positive).

@biobook or anyone. I know the title says "dropping antibody levels" but here we have a clear case of higher levels 2 weeks later (and about 7 months from presumed COVID-19 infection). Are there any other similar DP? Is it possible that the levels just fluctuate? What can influence them?
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Re: Dropping Antibody Levels
« Reply #224 on: October 22, 2020, 12:44:34 PM »
The corollary of that fix is that if there is a 5% chance that they are not immune it does not mean a 5% of transmitting. They would still need to become infected. So if someone Ab- has a 10% chance of being infected and able to transmit at a given time (this number is random and likely high) that would mean having a .5% chance of making the grandmother sick.
Yes, you're 100% right.   :D 
I just meant there's a real, though very small, chance that an Ab+ person will get sick or get others sick. 

Me: we're 95% certain they're not carrying the virus.
Avromie7: we're 95% certain they can't carry the virus.

For Israel, they just want to know if that person is carrying the virus on that flight, so I'm not sure what you're adding,  @avromie7