Author Topic: Dropping Antibody Levels  (Read 59826 times)

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Re: Dropping Antibody Levels
« Reply #240 on: December 18, 2020, 10:58:36 AM »
I wonder if Quest/Labcorp offices are giving quantitative results these days. Anyone know?
Anyplace in Cleveland where you can get an antibody test with a score result, not just positive/negative ?
^^^

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Re: Dropping Antibody Levels
« Reply #241 on: December 18, 2020, 11:03:11 AM »
Anyplace in Cleveland where you can get an antibody test with a score result, not just positive/negative ?
I'm told they don't offer it because nobody knows what the numbers mean yet.
Would have been nice to track the direction of the numbers though.
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Re: Dropping Antibody Levels
« Reply #242 on: January 04, 2021, 11:54:41 AM »
Just was tested for antibodies and came back negative. I was positive back in May (had most Covid symptoms in March but like most, could not get tested). Does a negative test actually mean it is negative or possibly just too low to be detected? Either way, I guess that means my immunity is gone??

Offline avromie7

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Re: Dropping Antibody Levels
« Reply #243 on: January 04, 2021, 12:29:41 PM »
Just was tested for antibodies and came back negative. I was positive back in May (had most Covid symptoms in March but like most, could not get tested). Does a negative test actually mean it is negative or possibly just too low to be detected? Either way, I guess that means my immunity is gone??
Immunity likely lasts way longer than antibodies, but you can't know for sure once the antibodies are gone.
I wonder what people who type "u" instead of "you" do with all their free time.

Offline biobook

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Re: Dropping Antibody Levels
« Reply #244 on: January 04, 2021, 12:48:20 PM »
Just was tested for antibodies and came back negative. I was positive back in May (had most Covid symptoms in March but like most, could not get tested). Does a negative test actually mean it is negative or possibly just too low to be detected? Either way, I guess that means my immunity is gone??
No, it doesn't necessarily indicate that your immunity is gone.  Antibodies produced to fight infection naturally start to decrease thereafter.  But that initial infection also creates permanent memory B cells that will rapidly produce Covid antibodies if needed in the future, as well as T cells.  So you may still have immunity.   

Why You Shouldn’t Worry About Studies Showing Waning Coronavirus Antibodies
https://www.nytimes.com/2020/10/27/health/coronavirus-antibodies-studies.html
HOWEVER, it's also possible that you don't have immunity any more.  The only way to know if someone is immune is to see if they become sick when re-exposed.  Among those who had a well-documented second infection with Covid, some of them did have measurable antibodies at the time they were re-infected.  Nobody knows why this did not protect them.  Was this unique to those few people?  Did they have some other immune deficiency?  Or is there really a level of antibody which is simply insufficient to fight off infection? 

For some other coronaviruses, immunity lasts just a few months to a year.  For other coronaviruses, it has lasted for decades.  Not enough time has passed to know how long immunity will last to this coronavirus, or how it might relate to their antibody level, which is why everyone is asked to wear masks and socially distance.

Offline avromie7

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Re: Dropping Antibody Levels
« Reply #245 on: January 04, 2021, 02:32:03 PM »
No, it doesn't necessarily indicate that your immunity is gone.  Antibodies produced to fight infection naturally start to decrease thereafter.  But that initial infection also creates permanent memory B cells that will rapidly produce Covid antibodies if needed in the future, as well as T cells.  So you may still have immunity.   
HOWEVER, it's also possible that you don't have immunity any more.  The only way to know if someone is immune is to see if they become sick when re-exposed.  Among those who had a well-documented second infection with Covid, some of them did have measurable antibodies at the time they were re-infected.  Nobody knows why this did not protect them.  Was this unique to those few people?  Did they have some other immune deficiency?  Or is there really a level of antibody which is simply insufficient to fight off infection? 

For some other coronaviruses, immunity lasts just a few months to a year.  For other coronaviruses, it has lasted for decades.  Not enough time has passed to know how long immunity will last to this coronavirus, or how it might relate to their antibody level, which is why everyone is asked to wear masks and socially distance.
Where did you see this? I haven't seen evidence of any confirmed reinfections while having measurable antibodies.
I wonder what people who type "u" instead of "you" do with all their free time.

Offline biobook

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Re: Dropping Antibody Levels
« Reply #246 on: January 04, 2021, 05:09:43 PM »
Where did you see this? I haven't seen evidence of any confirmed reinfections while having measurable antibodies.
It was reported in the first US case of reinfection in October, not sure now if that was the only case that also measured antibodies.
 
https://www.usatoday.com/story/news/health/2020/10/12/covid-reinfection-virus-can-strike-twice-worse-second-time-nevada-man/5965917002/
Excerpts:
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 April 27, he reported his symptoms had all resolved and he felt fine, but at the time, employees were required to test negative for the coronavirus twice before they would be allowed back to work, Kerwin said. So he remained isolated at home.

A month later, he began feeling poorly again. At the same time, there was an outbreak where one of his parents, also an essential worker, was employed, Kerwin said.

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.

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Re: Dropping Antibody Levels
« Reply #247 on: January 04, 2021, 05:18:42 PM »
It was reported in the first US case of reinfection in October, not sure now if that was the only case that also measured antibodies.
 
https://www.usatoday.com/story/news/health/2020/10/12/covid-reinfection-virus-can-strike-twice-worse-second-time-nevada-man/5965917002/
Excerpts:
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 April 27, he reported his symptoms had all resolved and he felt fine, but at the time, employees were required to test negative for the coronavirus twice before they would be allowed back to work, Kerwin said. So he remained isolated at home.

A month later, he began feeling poorly again. At the same time, there was an outbreak where one of his parents, also an essential worker, was employed, Kerwin said.

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.

There's some missing or conflicting information here.

For starters, you state that the first case of reinvention was in October, but this man tested positive again in early June?

Why wasn't he testing intermittently to get the 2 negatives needed to go back to work? Its been reported that the virus can linger in some and he may not have had reinfection in June, but rather a resurgence? I really don't know but there's stuff here that just doesn't add up.

Offline biobook

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Re: Dropping Antibody Levels
« Reply #248 on: January 04, 2021, 05:30:45 PM »
There's some missing or conflicting information here.

For starters, you state that the first case of reinvention was in October, but this man tested positive again in early June?
Sorry, I meant to say that it was reported in October, not that the reinfection happened then. 
Quote
Why wasn't he testing intermittently to get the 2 negatives needed to go back to work? Its been reported that the virus can linger in some and he may not have had reinfection in June, but rather a resurgence? I really don't know but there's stuff here that just doesn't add up.

He went for testing on April 18 and his infection with the coronavirus was confirmed.

On April 27, he reported his symptoms had all resolved and he felt fine, but at the time, employees were required to test negative for the coronavirus twice before they would be allowed back to work, Kerwin said. So he remained isolated at home.

A month later, he began feeling poorly again. At the same time, there was an outbreak where one of his parents, also an essential worker, was employed, Kerwin said.

I understood the bolded part to indicate that he DID have those two negative tests required to return to work. But I'll check the original article and see if it makes it clearer. 

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Re: Dropping Antibody Levels
« Reply #249 on: January 04, 2021, 05:38:34 PM »
It was reported in the first US case of reinfection in October, not sure now if that was the only case that also measured antibodies.
 
https://www.usatoday.com/story/news/health/2020/10/12/covid-reinfection-virus-can-strike-twice-worse-second-time-nevada-man/5965917002/
Excerpts:
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 April 27, he reported his symptoms had all resolved and he felt fine, but at the time, employees were required to test negative for the coronavirus twice before they would be allowed back to work, Kerwin said. So he remained isolated at home.

A month later, he began feeling poorly again. At the same time, there was an outbreak where one of his parents, also an essential worker, was employed, Kerwin said.

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.
Assumed he had antibodies? Doesn't say he was tested for antibodies before he got sick again

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Re: Dropping Antibody Levels
« Reply #250 on: January 04, 2021, 05:42:13 PM »
Several people, myself included, had rebound symptoms a few weeks after the first bout. But I wouldn't consider that a reinfection.
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Offline iluv2travel

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Re: Dropping Antibody Levels
« Reply #251 on: January 04, 2021, 06:09:58 PM »
I understood the bolded part to indicate that he DID have those two negative tests required to return to work. But I'll check the original article and see if it makes it clearer.

I understood it the exact opposite way.

He reported on 4/27 that his symptoms resolved and he felt fine. However, because he did NOT have the 2 negatives he remained in isolation. Why would he remain in isolation if he'd yes gotten the 2 required negatives?

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Re: Dropping Antibody Levels
« Reply #252 on: January 04, 2021, 06:34:41 PM »

Why wasn't he testing intermittently to get the 2 negatives needed to go back to work?
He had two negative tests on May 9 and May 26, according to the scientific article.
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30764-7/fulltext

Its been reported that the virus can linger in some and he may not have had reinfection in June, but rather a resurgence?
Several people, myself included, had rebound symptoms a few weeks after the first bout. But I wouldn't consider that a reinfection.
Right, resurgence/lingering/rebound symptoms can occur, and that makes it difficult to conclude that seemingly new symptoms are in fact a reinfection.  So to consider something a reinfection, they're focusing only on those cases where the genome was sequenced for both infections, and there are significant differences between them, which would imply exposure to a new virus, rather than resurgence of the first one. 

There are now 33 cases that meet that definition, and another 2325 suspected cases. https://bnonews.com/index.php/2020/08/covid-19-reinfection-tracker/
https://bnonews.com/index.php/reinfection-tracker-suspected-cases/

Compared to the number of primary infections, these are obviously tiny numbers, so still impossible to know whether these few people are rarities, and reinfection will be rare, or if these few people are the tip of the iceberg, and reinfections will increase over the next year. 

Assumed he had antibodies? Doesn't say he was tested for antibodies before he got sick again
Yes, you make an important point.  The USA Today reporter wrote "Again, the man tested positive for the virus, even though he still had antibodies to the virus in his bloodstream, Kerwin said."  But Kerwin et al's article in Lancet (link above) shows that antibodies were measured only on June 6, a day after the second positive virus test on June 5, and they hadn't tested for antibodies before then.  "A major limitation of our case study is that we were unable to undertake any assessment of the immune response to the first episode of SARS-CoV-2 infection. We also could not assess fully the effectiveness of the immune responses (eg, neutralising antibody titres) during the second episode, when the individual was antibody-positive for total antibody assay to the SARS-CoV-2 nucleocapsid protein."

So you're right, that it's possible that this person either failed to produce antibodies the first time (unlikely, since antibodies seem necessary for recovery), or made them and then they disappeared completely (unlikely, because antibodies are usually broken down slowly after infection is over).  But they agree that this missing data point makes it impossible to draw firm conclusions from this one case:

"If our patient is a case of reinfection, it is crucial to note that the frequency of such an occurrence is not defined by one case study: this event could be rare. The absence of comprehensive genomic sequencing of positive cases in the USA and worldwide limits the advances in public health surveillance needed to find these cases. Certainly, limitations in screening and testing availability for SARS-CoV-2 exacerbate the poor surveillance efforts being undertaken not only to diagnose COVID-19 but also to obtain actionable genetic tracking of this agent.

I understood it the exact opposite way.

He reported on 4/27 that his symptoms resolved and he felt fine. However, because he did NOT have the 2 negatives he remained in isolation. Why would he remain in isolation if he'd yes gotten the 2 required negatives?

He felt fine on 4/27, but because 2 negatives were required before returning to work, he remained in isolation at home and didn't return to work.  During that isolation, he had the two negative tests on May 9 and May 26, after which he came out of isolation and returned to work. 

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Re: Dropping Antibody Levels
« Reply #253 on: January 04, 2021, 07:09:02 PM »
Thanks for filling in the missing info.

So basically on 4/27 although he felt fine he remained in isolation because he didn't have 2 negatives yet. He only was able to exit isolation after 5/26 which was almost the time when he began feeling symptoms again (on 5/31).

Regarding the fact that he "still" had antibodies, if he was only first tested on June 6, perhaps those antibodies were only produced in response to the second infection? Its possible that a person should not produce antibodies. I'm not sure there is data on this but I do have anecdotal evidence from people I know who tested positive for COVID (with symptoms) but tested antibodies negative thereafter.

As much as we already know, I think there's still a lot we need to learn about this virus.

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Re: Dropping Antibody Levels
« Reply #254 on: January 04, 2021, 07:44:45 PM »
Thanks for filling in the missing info.

So basically on 4/27 although he felt fine he remained in isolation because he didn't have 2 negatives yet. He only was able to exit isolation after 5/26 which was almost the time when he began feeling symptoms again (on 5/31).
Right.  He might have picked up the second infection at work, or from someone living in his home who worked elsewhere, or, I suppose, from going for that second test...
Quote
Regarding the fact that he "still" had antibodies, if he was only first tested on June 6, perhaps those antibodies were only produced in response to the second infection?

Right. Earlier I had said "Among those who had a well-documented second infection with Covid, some of them did have measurable antibodies at the time they were re-infected" but I was relying on the USA Today article, which said "the man tested positive for the virus, even though he still had antibodies." 

But this article was based on the Lancet article, where they specifically regret not having antibody measurement before the second infection, so it does seem, as you suggest, that the man had no measurable antibodies on 5/26 (when he had the second negative test), was reinfected soon after, and began producing antibodies to that second infection.

Quote
Its possible that a person should not produce antibodies. I'm not sure there is data on this but I do have anecdotal evidence from people I know who tested positive for COVID (with symptoms) but tested antibodies negative thereafter.
Interesting.

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Re: Dropping Antibody Levels
« Reply #255 on: January 04, 2021, 07:53:31 PM »
... so it does seem, as you suggest, that the man had no measurable antibodies on 5/26 (when he had the second negative test), was reinfected soon after,

It seems that he probably was only able to be reinfected because he didn't produce antibodies the first time around.

I don't think there's ever been a case where a person was antibodies positive and COVID negative at least a few days prior to a reinfection.

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Re: Dropping Antibody Levels
« Reply #256 on: January 04, 2021, 08:11:20 PM »
It seems that he probably was only able to be reinfected because he didn't produce antibodies the first time around.
Well, we don't have any evidence to conclude that.  The effectiveness of any chemical in the body, or any drug we introduce into the body, is going to depend on the dose, or the amount.  A baby aspirin might not cure your headache, but a larger dose will.  It's possible that he did produce antibodies first time around, but a few weeks later they had declined to too low of a dose to effectively fight off infection.
Quote
I don't think there's ever been a case where a person was antibodies positive and COVID negative at least a few days prior to a reinfection.
There have been only 33 documented reinfections, and each one had different data collected about it, so it seems too early to say that there hasn't ever been such a case. 

I'll take a look at some of those 33 and see if any pop up.

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Re: Dropping Antibody Levels
« Reply #257 on: January 04, 2021, 08:17:26 PM »
Well, we don't have any evidence to conclude that.  The effectiveness of any chemical in the body, or any drug we introduce into the body, is going to depend on the dose, or the amount.  A baby aspirin might not cure your headache, but a larger dose will.  It's possible that he did produce antibodies first time around, but a few weeks later they had declined to too low of a dose to effectively fight off infection.

Yes, that's a likely scenario as well.


Quote
There have been only 33 documented reinfections, and each one had different data collected about it, so it seems too early to say that there hasn't ever been such a case. I'll take a look at some of those 33 and see if any pop up.

Would be very interesting if there was a confirmed COVID negative plus confirmed antibodies positive followed by a new COVID positive while there is/was potentially still antibodies. This would obviously be something extremely rare at this point given that 33 confirmed reinfections as a whole is minuscule.

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Re: Dropping Antibody Levels
« Reply #258 on: January 04, 2021, 08:20:44 PM »
It seems fair to say that we have not yet seen a single case worldwide where someone was antibody positive and was reinfected during that time.

(on the other hand there do seem to be some -very few- cases of general reinfection. both where no antibodies were ever recorded, as well as were antibodies had been previously been recorded but then dropped below detectable levels)

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Re: Dropping Antibody Levels
« Reply #259 on: January 05, 2021, 02:40:58 AM »
It seems fair to say that we have not yet seen a single case worldwide where someone was antibody positive and was reinfected during that time.

(on the other hand there do seem to be some -very few- cases of general reinfection. both where no antibodies were ever recorded, as well as were antibodies had been previously been recorded but then dropped below detectable levels)

There do seem to be a few cases that at least hint that someone was reinfected while antibody positive:

https://www.timesofisrael.com/81-israelis-suspected-of-being-reinfected-with-coronavirus-health-ministry/
Published in October:

    They told the story of a 20-year-old woman from Bnei Brak, healthy until she caught the coronavirus. She was diagnosed on April 17, and tested negative on May 1 and May 10.

    The doctors wrote: “During the first week of August 2020, after enjoying three months of health, some of her family members were symptomatic for COVID-19 and tested positive.” The patient then went for screening on August 6 and on August 11, and tested positive both times.

    Asked how sure she is about the reinfection diagnosis, Nachmias told The Times of Israel: “There is no room for doubt, there was clearly reinfection. We did the first tests while she was diagnosed to have the disease clinically, then she was clearly negative, and she was subsequently infected.”

    She said that upon the second infection, she had a blood sample drawn for analysis and found that antibodies were present. As most patients wouldn’t yet have antibodies so soon after infection, Nachmias said they were seemingly from the first infection, constituting extra evidence that the patient had, indeed, been infected back in April.

Another in Israel:
https://www.ynetnews.com/health_science/article/SJvLIxRnw
    After being declared free of the virus the first time, the man was released back to the geriatric care facility where he lived, while two further coronavirus tests also returned a negative result.
    But when a new outbreak of COVID-19 was detected in the facility, the man was tested once again and a positive result was returned....genetic testing at Sheba revealed that the second infection was from a different strain.
    According to medical officials, the lab's findings were bolstered by the fact that the man had produced a small amount of antibodies after his first infection.
From England: A large study of health care workers.  1246 tested antibody-positive in April.  They were invited for PCR tests for virus every two weeks, and antibody testing every two months, but it's not clear to me whether they were actually tested that often.  3 of them had a subsequent positive PCR picked up by this repeated screening, suggesting reinfection, but they were all asymptomatic.
https://directorsblog.nih.gov/2020/12/08/study-of-healthcare-workers-shows-covid-19-immunity-lasts-many-months/
The researchers say that because of the small number of reinfections, they can't draw any conclusions about the relative importance of current or past antibody level or T cells in preventing reinfection. 
https://www.medrxiv.org/content/10.1101/2020.11.18.20234369v1.full

So at this point, reinfections are rare, but we can't point to a certain level of antibodies that prevents them from occuring.