Dropping Antibody Levels

[Traveler718]

Where did he take it?

With our local (frum) family doctor, the same one who gave me the test in June. He's also the medical director at a large frum medical facility in Brooklyn, so he's extremely well-connected and knowledgeable. He tested my son on Sept. 8.

[Dan]

With our local (frum) family doctor, the same one who gave me the test in June. He's also the medical director at a large frum medical facility in Brooklyn, so he's extremely well-connected and knowledgeable.

I wonder if Quest/Labcorp offices are giving quantitative results these days. Anyone know?

[4yourinfo]

I took one test in May (idk which but it was the one where 15 is pos) and got 7, then I took the Roche test in July and it was pos. For whatever that's worth.

You may have been exposed - which boosted your antibodies

[etech0]

You may have been exposed - which boosted your antibodies

Do you mean between the two tests?
I had some symptoms in March but didn't test for the virus

[Joe4007]

I wonder if Quest/Labcorp offices are giving quantitative results these days. Anyone know?

Tested with Quest last week and didn't get a quantitative result.

[Dan]

Tested with Quest last week and didn't get a quantitative result.

Bummer, thanks.
Anyone use Labcorp recently?

[Dan]

Looks like clinical trials only
https://www.labcorp.com/coronavirus-disease-covid-19/news/labcorp-launches-quantitative-antibody-test-assess-effectiveness-covid-19-vaccines-clinical-trials

[biobook]

Looks like clinical trials only
https://www.labcorp.com/coronavirus-disease-covid-19/news/labcorp-launches-quantitative-antibody-test-assess-effectiveness-covid-19-vaccines-clinical-trials

And that press release you posted says "... the level of antibodies needed to be considered immune to SARS-CoV-2 is yet to be determined" so even if you had a number, you wouldn't know if it met some threshold for immunity.

The only way to know what level of antibody prevents re-infection is to wait for re-infections to occur, and examine the antibody level at that time.  There have been only 23 (?) confirmed reinfections worldwide.  We discussed one of these last week:

"The Nevada man, considered an essential worker, started feeling ill in late March, with a sore throat, cough, headache, nausea and diarrhea...He went for testing on April 18 and his infection with the coronavirus was confirmed....

"On May 31, he went to an urgent care center, reporting fever, headache, dizziness, cough, nausea and diarrhea. On June 5, he went to see a doctor who found his oxygen levels dangerously low and had him hospitalized. Again, the man tested positive for the virus, even though he still had antibodies to the virus in his bloodstream, Kerwin said."

https://www.usatoday.com/story/news/health/2020/10/12/covid-reinfection-virus-can-strike-twice-worse-second-time-nevada-man/5965917002/

[Dan]

And that press release you posted says "... the level of antibodies needed to be considered immune to SARS-CoV-2 is yet to be determined" so even if you had a number, you wouldn't know if it met some threshold for immunity.

The only way to know what level of antibody prevents re-infection is to wait for re-infections to occur, and examine the antibody level at that time.  There have been only 23 (?) confirmed reinfections worldwide.  We discussed one of these last week:

"The Nevada man, considered an essential worker, started feeling ill in late March, with a sore throat, cough, headache, nausea and diarrhea...He went for testing on April 18 and his infection with the coronavirus was confirmed....

"On May 31, he went to an urgent care center, reporting fever, headache, dizziness, cough, nausea and diarrhea. On June 5, he went to see a doctor who found his oxygen levels dangerously low and had him hospitalized. Again, the man tested positive for the virus, even though he still had antibodies to the virus in his bloodstream, Kerwin said."

https://www.usatoday.com/story/news/health/2020/10/12/covid-reinfection-virus-can-strike-twice-worse-second-time-nevada-man/5965917002/

Sure, but it would allow you to track the movement of your own antibodies over time.

[AsherO]

Anyone know the relative scale/range for the Roche test that NYC Health and Hospitals administers?

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 didn’t say which test it was, it was called “COVID-19 Total Antibody”.

ETA:

The results included the following two links which imply it’s the Roche test. The PDFs in the links don’t 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

[meme]

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 didn’t say which test it was, it was called “COVID-19 Total Antibody”.

ETA:

The results included the following two links which imply it’s the Roche test. The PDFs in the links don’t 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?

[AsherO]

Where did you take this test?

Kings County hospital’s walk-in COVID testing. It’s in tents outside the D building (I think that’s what it’s called).

[username]

Labcor  @ walgreens just says postive or negative.

[Dan]

Labcor  @ walgreens just says postive or negative.

Which test was it?

[biobook]

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! 

[ExGingi]

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).

[username]

Which test was it?

[skyguy918]

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.

[biobook]

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.

[skyguy918]

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.