The Next Pandemic: SARS-CoV-2/COVID-19

[Buffalo Bills Fan]

Studies Report Rapid Loss of COVID-19 Antibodies

The results, while preliminary, suggest that survivors of SARS-CoV-2 infection may be susceptible to reinfection within weeks or months.

Amanda Heidt

Jun 19, 2020

14.5K

ABOVE: © ISTOCK.COM, CHRISTOPH BURGSTEDT

Apair of studies published this week is shedding light on the duration of immunity following COVID-19, showing patients lose their IgG antibodies—the virus-specific, slower-forming antibodies associated with long-term immunity—within weeks or months after recovery. With COVID-19, most people who become infected do produce antibodies, and even small amounts can still neutralize the virus in vitro, according to earlier work. These latest studies could not determine if a lack of antibodies leaves people at risk of reinfection.

One of the studies found that 10 percent of nearly 1,500 COVID-positive patients registered undetectable antibody levels within weeks of first showing symptoms, while the other of 74 patients found they typically lost their antibodies two to three months after recovering from the infection, especially among those who tested positive but were asymptomatic. 

In contrast, infections caused by coronavirus cousins such as SARS and MERS result in antibodies that remain in the body for nearly a year, according to The New York Times.

The first study, published June 16 on the preprint server medRxiv, screened for antibodies in almost 1,500 coronavirus patients in Wuhan, China. The researchers compared their levels to three other groups: nearly 20,000 members of the general population; more than 1,600 patients hospitalized for reasons other than COVID-19; and more than 3,800 medical workers, whom the authors assumed had “inevitably” been exposed to the virus in its early days, meaning they should have developed antibodies.

They found that while almost 90 percent of COVID-19 patients had antibodies, roughly 1 percent to 5 percent of individuals in the others groups had them as well. The authors conclude in their paper that the remaining 10 percent of infected patients with no detectable antibodies, combined with the lack of antibodies in healthcare workers, suggest that “after SARS-CoV-2 infection, people are unlikely to produce long-lasting protective antibodies against this virus.”

https://www.the-scientist.com/news-opinion/studies-report-rapid-loss-of-covid-19-antibodies-67650

 

Cousin to this covid19 report says only a year of antibodies only last.  Not for sure but really need more studies how long antibodies last. Why I don't comment antibodies until real research. Some say this covid19 only two months antibodies( who knows)

 

Emerg Infect Dis. 2007 Oct; 13(10): 1562–1564.

doi: 10.3201/eid1310.070576

PMCID: PMC2851497

PMID: 18258008

Duration of Antibody Responses after Severe Acute Respiratory Syndrome

Li-Ping Wu,^* Nai-Chang Wang,^* Yi-Hua Chang,^* Xiang-Yi Tian,^* Dan-Yu Na,^* Li-Yuan Zhang,^* Lei Zheng,^* Tao Lan,^† Lin-Fa Wang,^‡ and Guo-***** Liang^§

Author information Copyright and License information Disclaimer

 

This article has been cited by other articles in PMC.

 

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Abstract

Among 176 patients who had had severe acute respiratory syndrome (SARS), SARS-specific antibodies were maintained for an average of 2 years, and significant reduction of immunoglobulin G–positive percentage and titers occurred in the third year. Thus, SARS patients might be susceptible to reinfection >3 years after initial exposure.

Keywords: SARS, convalescent, antibodies, longitudinal study, dispatch

Severe acute respiratory syndrome (SARS) represents the first pandemic transmissible disease to emerge in this century. It was caused by a previously unknown coronavirus, the SARS-associated coronavirus (SARS-CoV) (1). SARS-CoV spreads from animals to humans by a rapid adaptation and evolution process (2,3). A large number of closely related viruses are present in wildlife reservoir populations (4–6). Therefore, due to cross-species transmission of the same or a similar coronavirus, SARS could recur. Immune protection against infection with other human coronaviruses, such as OC43 and 229E, is short-lived (7). To assess SARS patients’ risk for future reinfection, we conducted a longitudinal study of immunity in convalescent patients.

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The Study

Shanxi Province in China was 1 of the SARS epicenters during the 2002–03 outbreaks. For our study, serum samples were taken from patients in 7 designated SARS hospitals in the province during March–August 2003. Follow-up serum samples were taken at 6 months, 1, 2, and 3 years after the onset of symptoms. A total of 176 cases that met the World Health Organization (WHO) SARS case definition (8) and had known transmission history were included in this study. The study was conducted as part of a national SARS control and prevention program; use of serum from human participants was approved by the Committee for SARS Control and Prevention, Department of Science and Technology, the People’s Republic of China.

Titers of serum antibodies to SARS-CoV were determined by using a commercially available ELISA kit (BJI-GBI Biotechnology, Beijing, China). The ELISA was based on an inactivated preparation of whole-virus lysate. The kit was the first commercial kit approved by the Chinese Food and Drug Administration for specific detection of SARS-CoV antibodies and has been widely used in several studies (9–11). Manufacturer’s instructions were followed without modification. Briefly, for every ELISA plate, 1 blank, 1 positive, and 2 negative controls were included. For detection of immunoglobulin G (IgG), a 1:10 dilution of testing serum (100 μL) was added to antigen-coated wells, and the plate was incubated at 37^oC for 30 min. Horseradish peroxide (HRP)–conjugated antihuman IgG (100 μL) was then added for detection of bound antibodies. For detection of IgM, the incubation of primary antibodies was extended to 60 min, followed by detection with HRP-conjugated antihuman IgM. Optical density (OD) readings were deemed valid only when the negative control OD was <0.10 and the positive control was >0.50 on the same ELISA plate. The cutoff for IgG and IgM determination was defined as 0.13 and 0.11, respectively, plus OD of the negative control. When the OD of the negative control was <0.05, 0.05 was used for the calculation. In this study, the OD readings of negative controls from different testing were consistently <0.05, so the cutoff ODs for IgG and IgM were 0.18 and 0.16, respectively. Serum samples that had an OD greater than or equal to the cutoff value were considered positive. Weak positive samples (i.e., OD<2× cutoff value) were retested in duplicate on the same day; only reproducible positive results were included in the final analysis. All data were processed by using Excel version 7.0 (Microsoft Corp., Redmond, WA, USA) and SPSS software version 10 for Windows (SPSS Inc., Chicago, IL, USA).

Among the cohort, 163 (92.61%) of 176 (χ² = 200.11, p = 0.000002) were IgG positive, which indicated that most patients who met the WHO case definition were indeed infected with SARS-CoV. As shown in the Table, at ≈7 days after the onset of symptoms, the percentage who were IgG positive was ≈11.80%. This percentage continued to increase, reached 100% at 90 days, and remained largely unchanged up to 200 days. Furthermore, after 1 and 2 years 93.88% and 89.58% of patients, respectively, were IgG positive, which suggests that the immune responses were maintained in >90% of patients for 2 years. However, 3 years later, ≈50% of the convalescent population had no SARS-CoV–specific IgG. The OD changes correlated with the changes to the IgG-positive percentage, although the rate of change varied. Both the OD readings (0.93) and positive percentages peaked at 90–120 days; however, the rate of reduction of the average OD readings was much faster, dropping by 22% (0.73) and 40% (0.54) at 1 and 2 years, respectively, after symptom onset (Figure 1).

 

Figure 1

Change of immunoglobulin G (IgG) patterns among 176 convalescent severe acute respiratory syndrome patients with known transmission history. See the Table for number of samples used for the calculation at each time point. OD, optical density.

A similar observation was obtained for IgM trends in this same cohort. The percentage of patients who were IgM positive within the first 7 days was 21.4% and peaked at 76.2% after 21–30 days (Table). The patterns of IgM-positive percentage and average OD readings were similar; both peaked at 21–30 days. After 60 days, the average OD readings dropped to 0.167, close to the cutoff value of 0.160.

Table

Cumulative rates of SARS-CoV antibodies among 176 SARS patients with known transmission histories*

Time after symptom onset, d	IgG				IgM†
	No. samples tested	No. positive samples (%)	Average OD		No. samples tested	No. positive samples (%)	Average OD
0–7	17	2 (11.76)	0.046		14	3 (21.43)	0.136
8–14	26	10 (38.46)	0.190		22	14 (63.64)	0.312
15–20	22	17 (77.27)	0.351		19	12 (63.16)	0.477
21–30	36	33 (91.67)	0.493		21	16 (76.19)	0.560
31–60	72	67 (93.06)	0.627		22	14 (63.64)	0.320
61–90	35	33 (94.29)	0.745		15	5 (33.33)	0.167
91–120	11	11 (100.00)	0.965		ND	ND	ND
121–210	23	23 (100.00)	0.932		ND	ND	ND
211–365	49	46 (93.88)	0.734		ND	ND	ND
366–763	96	86 (89.58)	0.535		ND	ND	ND
764–1,265	28	15 (53.57)	0.250		ND	ND	ND

*SARS-CoV, severe acute respiratory syndrome–associated coronavirus; Ig, immunoglobulin; OD, optical density; ND, not determined because for most samples the IgM readings already reached background level on day 90.
†For some patients, we did not have enough serum to test for IgM after testing for IgG; hence, a smaller number of serum samples were tested for IgM than for IgG.

Among the cohort of patients with known transmission histories, we were able to obtain a complete collection of serum samples from 18 patients at 6 months, 1, 2, and 3 years. The IgG levels of these 18 patients were analyzed separately to obtain an IgG trend that more accurately represented convalescent SARS patients (Figure 2). All 18 patients had positive IgG at 6 months and at 1 year (i.e., 100% positive); only 1 patient became IgG negative at 2 years. However, at 3 years, the positive percentage dropped to 55.56%. The reduction of OD values mimicked that of the positive percentage, again at a faster rate. The average OD readings dropped from 0.94 at 6 months to 0.64 at 1 year, which represents a reduction of 33.33%. The OD further dropped to 0.52 (45.83% reduction) by 2 years and to 0.25 by 3 years.

 

Figure 2

Change of immunoglobulin G (IgG) patterns among 18 convalescent severe acute respiratory syndrome patients with a complete collection of sequential serum samples at the time points shown. The 18 patients were selected from the cohort of 176 patients for whom transmission history was known. OD, optical density.

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Conclusions

To our knowledge, the 3-year follow-up conducted in this study is the longest longitudinal study ever reported. With a large number of patients who had confirmed transmission history (176) and a complete dataset for 18, the level of confidence is high that the results obtained in this study are representative for convalescent SARS patients. Similar results have been reported from longitudinal studies of SARS patients with smaller cohort size (18–98 patients) and shorter follow-up period (240 days to 2 years) (9–14). The general trend of IgM peaking at ≈1 month after symptom onset and IgG peaking at 2–4 months was consistent among different studies.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/

 

Cousin to covid19 antibodies in the past. Real research on 

 

Edited June 25, 2020 by Buffalo Bills Fan

[shoshin]

1 hour ago, Buffalo Bills Fan said:

Studies Report Rapid Loss of COVID-19 Antibodies

The results, while preliminary, suggest that survivors of SARS-CoV-2 infection may be susceptible to reinfection within weeks or months.

Amanda Heidt

Jun 19, 2020

14.5K

ABOVE: © ISTOCK.COM, CHRISTOPH BURGSTEDT

Apair of studies published this week is shedding light on the duration of immunity following COVID-19, showing patients lose their IgG antibodies—the virus-specific, slower-forming antibodies associated with long-term immunity—within weeks or months after recovery. With COVID-19, most people who become infected do produce antibodies, and even small amounts can still neutralize the virus in vitro, according to earlier work. These latest studies could not determine if a lack of antibodies leaves people at risk of reinfection.

One of the studies found that 10 percent of nearly 1,500 COVID-positive patients registered undetectable antibody levels within weeks of first showing symptoms, while the other of 74 patients found they typically lost their antibodies two to three months after recovering from the infection, especially among those who tested positive but were asymptomatic. 

 

 

 

 

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

Edited June 25, 2020 by shoshin

[Taro T]

5 minutes ago, shoshin said:

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

 

Really can't see a single person here not hoping they come up with an effective vaccine.

 

But several do take exception to the sentiment (which isn't yours) that nothing should fully reopen until a vaccine is available.  There's predictions one could be ready by October, but they really don't know whether that prediction will bear out.  We can't stay closed until there's a vaccine.  

[shoshin]

9 minutes ago, Taro T said:

 

Really can't see a single person here not hoping they come up with an effective vaccine.

 

Safe to say that most posters in this thread, when it came up earlier, said they would not take the vaccine. 

 

Some fear that Bill Gates is going to inject them with Microsoft Nanobots (TM). Others are afraid. Others say there's nothing to worry about. But definitely a wide majority. 

 

Quote

 

But several do take exception to the sentiment (which isn't yours) that nothing should fully reopen until a vaccine is available.  There's predictions one could be ready by October, but they really don't know whether that prediction will bear out.  We can't stay closed until there's a vaccine.  

 

We need to be open. But with eyes wide. I don't put a lot of weight into that study until we see larger samples. I'm surprised we haven't seen more on this, although it's hard to get much of a view since we have so few confirmed patients from 6 months ago. 

Edited June 25, 2020 by shoshin

[Taro T]

1 minute ago, shoshin said:

 

Safe to say that most posters in this thread, when it came up earlier, said they would not take the vaccine. 

 

Some fear that Bill Gates is going to inject them with Microsoft Nanobots (TM). Others are afraid. Others say there's nothing to worry about. But definitely a wide majority. 

 

 

We need to be open. But with eyes wide. I don't put a lot of weight into that study until we see larger samples. I'm surprised we haven't seen more on this, although it's hard to get much of a view since we have so few confirmed patients from 6 months ago. 

 

Personally, as am not in a high risk group, would not be one of the 1st to take the vaccine.  But, if it proves effective & side effects prove to be minimal, would most likely eventually get it.

 

But that has little to do with Bill Gates and more to do with undersanding that there's no way the vaccine will undergo the normal vetting protocols & the alpha test is rarely as good as the beta version & they could likely still plan improvements beyond that improving the efficacy & decreasing the side effects.  Were my status be more high risk, would be willing to be way closer to the front of the line.

[FireChans]

26 minutes ago, shoshin said:

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

Hey dude. How does a vaccine work?

[Buffalo Bills Fan]

28 minutes ago, shoshin said:

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

 

Agree first part. 

 

Want a safe and effective vaccine.  Understandable some people question it. Have questions as well. Until proves help people out.

[shoshin]

11 minutes ago, FireChans said:

Hey dude. How does a vaccine work?

 

Depends on the vaccine. 

[FireChans]

12 minutes ago, shoshin said:

 

Depends on the vaccine. 

What vaccines work long term that don’t involve IgG?

[shoshin]

5 minutes ago, FireChans said:

What vaccines work long term that don’t involve IgG?

 

I'm not an immunologist so I can't say know but based on what I do know, I suspect not many. IgG is usually the key antibody to activate. 

 

@Hapless Bills Fanis not an immunologist but she has more chops than most here and is often willing to drop into this place for a learned moment. Can you weigh in on his question and give your thoughts on the study pasted awkwardly in a few posts above that posits that patients may lose their immunity to Covid-19 quickly? If you want to respond outside the conspiracy-zone and discuss the study on OTW, I respect that. 

 

[fansince88]

34 minutes ago, FireChans said:

Hey dude. How does a vaccine work?

Better question is what else are you sticking in the vaccine and what does thst do to you over time?

[FireChans]

4 minutes ago, fansince88 said:

Better question is what else are you sticking in the vaccine and what does thst do to you over time?

Well, I haven’t seen a vaccine kill 100,000 people in 3 months.

[Chef Jim]

4 hours ago, Penfield45 said:

 

are you dumb? 

 

EU has a LARGER population than America and has far less confirmed cases. what the hell does sq miles have to do with anything lol

 

if anything, EU is far more densely populated than America and still managed to outdo the US in handeling the virus. there is no "crusade". America should be ashamed at how they have handled this pandemic. 

 

I'm going to jump in here and ask a question that may have already been asked/answered so forgive me.  What percentage of the EU population has been tested vs the US? 

1 hour ago, shoshin said:

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

 

How many? 

[B-Man]

 

 

Quick reminder from yesterday:

 

Oregon Takes Being Woke to the Next Level, Shows the Coronavirus Response Is a Total Joke

 

 

 

 

[Magox]

New Jersey did a “probable death” data dump.

 

Excluding that the death count continues to defy odds and marches downward.   My guess about a month ago was that we would most likely bottom out at around 500 deaths a day.   7 day average right now is around 600.

 

[BillsFanNC]

2 hours ago, Buffalo Bills Fan said:

Studies Report Rapid Loss of COVID-19 Antibodies

The results, while preliminary, suggest that survivors of SARS-CoV-2 infection may be susceptible to reinfection within weeks or months.

Amanda Heidt

Jun 19, 2020

14.5K

ABOVE: © ISTOCK.COM, CHRISTOPH BURGSTEDT

Apair of studies published this week is shedding light on the duration of immunity following COVID-19, showing patients lose their IgG antibodies—the virus-specific, slower-forming antibodies associated with long-term immunity—within weeks or months after recovery. With COVID-19, most people who become infected do produce antibodies, and even small amounts can still neutralize the virus in vitro, according to earlier work. These latest studies could not determine if a lack of antibodies leaves people at risk of reinfection.

One of the studies found that 10 percent of nearly 1,500 COVID-positive patients registered undetectable antibody levels within weeks of first showing symptoms, while the other of 74 patients found they typically lost their antibodies two to three months after recovering from the infection, especially among those who tested positive but were asymptomatic. 

In contrast, infections caused by coronavirus cousins such as SARS and MERS result in antibodies that remain in the body for nearly a year, according to The New York Times.

The first study, published June 16 on the preprint server medRxiv, screened for antibodies in almost 1,500 coronavirus patients in Wuhan, China. The researchers compared their levels to three other groups: nearly 20,000 members of the general population; more than 1,600 patients hospitalized for reasons other than COVID-19; and more than 3,800 medical workers, whom the authors assumed had “inevitably” been exposed to the virus in its early days, meaning they should have developed antibodies.

They found that while almost 90 percent of COVID-19 patients had antibodies, roughly 1 percent to 5 percent of individuals in the others groups had them as well. The authors conclude in their paper that the remaining 10 percent of infected patients with no detectable antibodies, combined with the lack of antibodies in healthcare workers, suggest that “after SARS-CoV-2 infection, people are unlikely to produce long-lasting protective antibodies against this virus.”

https://www.the-scientist.com/news-opinion/studies-report-rapid-loss-of-covid-19-antibodies-67650

 

Cousin to this covid19 report says only a year of antibodies only last.  Not for sure but really need more studies how long antibodies last. Why I don't comment antibodies until real research. Some say this covid19 only two months antibodies( who knows)

 

Emerg Infect Dis. 2007 Oct; 13(10): 1562–1564.

doi: 10.3201/eid1310.070576

PMCID: PMC2851497

PMID: 18258008

Duration of Antibody Responses after Severe Acute Respiratory Syndrome

Li-Ping Wu,^* Nai-Chang Wang,^* Yi-Hua Chang,^* Xiang-Yi Tian,^* Dan-Yu Na,^* Li-Yuan Zhang,^* Lei Zheng,^* Tao Lan,^† Lin-Fa Wang,^‡ and Guo-***** Liang^§

Author information Copyright and License information Disclaimer

 

This article has been cited by other articles in PMC.

 

Go to:

Abstract

Among 176 patients who had had severe acute respiratory syndrome (SARS), SARS-specific antibodies were maintained for an average of 2 years, and significant reduction of immunoglobulin G–positive percentage and titers occurred in the third year. Thus, SARS patients might be susceptible to reinfection >3 years after initial exposure.

Keywords: SARS, convalescent, antibodies, longitudinal study, dispatch

Severe acute respiratory syndrome (SARS) represents the first pandemic transmissible disease to emerge in this century. It was caused by a previously unknown coronavirus, the SARS-associated coronavirus (SARS-CoV) (1). SARS-CoV spreads from animals to humans by a rapid adaptation and evolution process (2,3). A large number of closely related viruses are present in wildlife reservoir populations (4–6). Therefore, due to cross-species transmission of the same or a similar coronavirus, SARS could recur. Immune protection against infection with other human coronaviruses, such as OC43 and 229E, is short-lived (7). To assess SARS patients’ risk for future reinfection, we conducted a longitudinal study of immunity in convalescent patients.

Go to:

The Study

Shanxi Province in China was 1 of the SARS epicenters during the 2002–03 outbreaks. For our study, serum samples were taken from patients in 7 designated SARS hospitals in the province during March–August 2003. Follow-up serum samples were taken at 6 months, 1, 2, and 3 years after the onset of symptoms. A total of 176 cases that met the World Health Organization (WHO) SARS case definition (8) and had known transmission history were included in this study. The study was conducted as part of a national SARS control and prevention program; use of serum from human participants was approved by the Committee for SARS Control and Prevention, Department of Science and Technology, the People’s Republic of China.

Titers of serum antibodies to SARS-CoV were determined by using a commercially available ELISA kit (BJI-GBI Biotechnology, Beijing, China). The ELISA was based on an inactivated preparation of whole-virus lysate. The kit was the first commercial kit approved by the Chinese Food and Drug Administration for specific detection of SARS-CoV antibodies and has been widely used in several studies (9–11). Manufacturer’s instructions were followed without modification. Briefly, for every ELISA plate, 1 blank, 1 positive, and 2 negative controls were included. For detection of immunoglobulin G (IgG), a 1:10 dilution of testing serum (100 μL) was added to antigen-coated wells, and the plate was incubated at 37^oC for 30 min. Horseradish peroxide (HRP)–conjugated antihuman IgG (100 μL) was then added for detection of bound antibodies. For detection of IgM, the incubation of primary antibodies was extended to 60 min, followed by detection with HRP-conjugated antihuman IgM. Optical density (OD) readings were deemed valid only when the negative control OD was <0.10 and the positive control was >0.50 on the same ELISA plate. The cutoff for IgG and IgM determination was defined as 0.13 and 0.11, respectively, plus OD of the negative control. When the OD of the negative control was <0.05, 0.05 was used for the calculation. In this study, the OD readings of negative controls from different testing were consistently <0.05, so the cutoff ODs for IgG and IgM were 0.18 and 0.16, respectively. Serum samples that had an OD greater than or equal to the cutoff value were considered positive. Weak positive samples (i.e., OD<2× cutoff value) were retested in duplicate on the same day; only reproducible positive results were included in the final analysis. All data were processed by using Excel version 7.0 (Microsoft Corp., Redmond, WA, USA) and SPSS software version 10 for Windows (SPSS Inc., Chicago, IL, USA).

Among the cohort, 163 (92.61%) of 176 (χ² = 200.11, p = 0.000002) were IgG positive, which indicated that most patients who met the WHO case definition were indeed infected with SARS-CoV. As shown in the Table, at ≈7 days after the onset of symptoms, the percentage who were IgG positive was ≈11.80%. This percentage continued to increase, reached 100% at 90 days, and remained largely unchanged up to 200 days. Furthermore, after 1 and 2 years 93.88% and 89.58% of patients, respectively, were IgG positive, which suggests that the immune responses were maintained in >90% of patients for 2 years. However, 3 years later, ≈50% of the convalescent population had no SARS-CoV–specific IgG. The OD changes correlated with the changes to the IgG-positive percentage, although the rate of change varied. Both the OD readings (0.93) and positive percentages peaked at 90–120 days; however, the rate of reduction of the average OD readings was much faster, dropping by 22% (0.73) and 40% (0.54) at 1 and 2 years, respectively, after symptom onset (Figure 1).

 

Figure 1

Change of immunoglobulin G (IgG) patterns among 176 convalescent severe acute respiratory syndrome patients with known transmission history. See the Table for number of samples used for the calculation at each time point. OD, optical density.

A similar observation was obtained for IgM trends in this same cohort. The percentage of patients who were IgM positive within the first 7 days was 21.4% and peaked at 76.2% after 21–30 days (Table). The patterns of IgM-positive percentage and average OD readings were similar; both peaked at 21–30 days. After 60 days, the average OD readings dropped to 0.167, close to the cutoff value of 0.160.

Table

Cumulative rates of SARS-CoV antibodies among 176 SARS patients with known transmission histories*

Time after symptom onset, d	IgG				IgM†
	No. samples tested	No. positive samples (%)	Average OD		No. samples tested	No. positive samples (%)	Average OD
0–7	17	2 (11.76)	0.046		14	3 (21.43)	0.136
8–14	26	10 (38.46)	0.190		22	14 (63.64)	0.312
15–20	22	17 (77.27)	0.351		19	12 (63.16)	0.477
21–30	36	33 (91.67)	0.493		21	16 (76.19)	0.560
31–60	72	67 (93.06)	0.627		22	14 (63.64)	0.320
61–90	35	33 (94.29)	0.745		15	5 (33.33)	0.167
91–120	11	11 (100.00)	0.965		ND	ND	ND
121–210	23	23 (100.00)	0.932		ND	ND	ND
211–365	49	46 (93.88)	0.734		ND	ND	ND
366–763	96	86 (89.58)	0.535		ND	ND	ND
764–1,265	28	15 (53.57)	0.250		ND	ND	ND

*SARS-CoV, severe acute respiratory syndrome–associated coronavirus; Ig, immunoglobulin; OD, optical density; ND, not determined because for most samples the IgM readings already reached background level on day 90.
†For some patients, we did not have enough serum to test for IgM after testing for IgG; hence, a smaller number of serum samples were tested for IgM than for IgG.

Among the cohort of patients with known transmission histories, we were able to obtain a complete collection of serum samples from 18 patients at 6 months, 1, 2, and 3 years. The IgG levels of these 18 patients were analyzed separately to obtain an IgG trend that more accurately represented convalescent SARS patients (Figure 2). All 18 patients had positive IgG at 6 months and at 1 year (i.e., 100% positive); only 1 patient became IgG negative at 2 years. However, at 3 years, the positive percentage dropped to 55.56%. The reduction of OD values mimicked that of the positive percentage, again at a faster rate. The average OD readings dropped from 0.94 at 6 months to 0.64 at 1 year, which represents a reduction of 33.33%. The OD further dropped to 0.52 (45.83% reduction) by 2 years and to 0.25 by 3 years.

 

Figure 2

Change of immunoglobulin G (IgG) patterns among 18 convalescent severe acute respiratory syndrome patients with a complete collection of sequential serum samples at the time points shown. The 18 patients were selected from the cohort of 176 patients for whom transmission history was known. OD, optical density.

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Conclusions

To our knowledge, the 3-year follow-up conducted in this study is the longest longitudinal study ever reported. With a large number of patients who had confirmed transmission history (176) and a complete dataset for 18, the level of confidence is high that the results obtained in this study are representative for convalescent SARS patients. Similar results have been reported from longitudinal studies of SARS patients with smaller cohort size (18–98 patients) and shorter follow-up period (240 days to 2 years) (9–14). The general trend of IgM peaking at ≈1 month after symptom onset and IgG peaking at 2–4 months was consistent among different studies.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/

 

Cousin to covid19 antibodies in the past. Real research on 

 

 

 

This study is talking about IgG levels waning after initial exposure, which is to be expected to an extent.  The ELISA tests that they use to track IgG levels is a very sensitive immunological assay.  The real question with these SARS patients is how would they respond when re-challenged with the virus?  That's an impossible study to perform since it would be unethical to give patients another dose of SARS.  It could be that these patients adaptive immunity could be strong upon re-challenge through memory T cell cascade of events, or not.  Same question for covid19.  Here's a good review of how vaccine immunity works and the innate vs. adaptive immune response.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068582/

 

Quote

From a literature review of the current literature, this article provides an introduction to vaccine immunology including a primer on the components of the immune system, passive vs. active immunization, the mechanism(s) by which immunizations stimulate(s) immunity, and the types of vaccines available. Both the innate and adaptive immune subsystems are necessary to provide an effective immune response to an immunization. Further, effective immunizations must induce long-term stimulation of both the humoral and cell-mediated arms of the adaptive system by the production of effector cells and memory cells. At least seven different types of vaccines are currently in use or in development that produce this effective immunity and have contributed greatly to the prevention of infectious disease around the world.

 

Edited June 25, 2020 by BillsFanNC

[DrW]

34 minutes ago, Chef Jim said:

 

I'm going to jump in here and ask a question that may have already been asked/answered so forgive me.  What percentage of the EU population has been tested vs the US? 

 

 

 

According to this web site https://ourworldindata.org/coronavirus#coronavirus-country-profiles the total number of tests in the US up to today is around 28 M.  They do not give numbers for the EU as a single entity, but when you add up the numbers from individual countries you get 14 M for Germany, Italy and Spain combined. The four most populous countries in the EU are these three plus France; data for France seem to be missing. Germany, Italy and Spain have a total population of 190 M, compared to 330 M for the US. Thus, I would say that the percentage of the population that has been tested on both sides of the Atlantic is similar. 

[GG]

14 minutes ago, DrW said:

 

According to this web site https://ourworldindata.org/coronavirus#coronavirus-country-profiles the total number of tests in the US up to today is around 28 M.  They do not give numbers for the EU as a single entity, but when you add up the numbers from individual countries you get 14 M for Germany, Italy and Spain combined. The four most populous countries in the EU are these three plus France; data for France seem to be missing. Germany, Italy and Spain have a total population of 190 M, compared to 330 M for the US. Thus, I would say that the percentage of the population that has been tested on both sides of the Atlantic is similar. 

 

On a per 1K basis, and taking account of size, US is #4 in testing for a country >40 million.  I'm guessing it will move to #1 soon, as more people in CA, FL and TX get tested

[Koko78]

3 hours ago, shoshin said:

 

It's not a large study and it has some testing weaknesses but if this turns out to be the case, it would suggest that the "let's go get herd immunity" is not going to work. I hope the IgG detection was flawed or not sensitive enough--the authors not that may be an issue. But they also note that other similar viruses do not always produce long term immunity. 

 

Come on vaccines.*

 

*I know the use of vaccines offends many posters in this thread. I hope you change your minds. 

 

Uh, how do you think a vaccine will be a panacea if the antibodies go away within weeks?

[shoshin]

37 minutes ago, Koko78 said:

 

Uh, how do you think a vaccine will be a panacea if the antibodies go away within weeks?

 

Uh the IgG antibodies don't go away within weeks. The IgA ones do. 

 

And If you have a vaccine that gives you Covid IgG antibodies for a few months, you could--if nearly everyone (the present 90% of PPP posters excluded, ahem) gets a few cycles of the vaccine--control the spread of the disease in pretty short order. 

 

We can see in that initial study that different types of cases (asymptomatic vs symptomatic) were significant contributors to the length of time that the IgG antibodies were detected (which is not necessarily an indicator of the end of immunity). So it possible (but who knows) that a vaccine might provide longer immunity. But none of us knows how long the vaccine would be effective for--I am sure the studies are watching this closely. 

Edited June 26, 2020 by shoshin