5 ms·

What mechanism are you suggesting would be at fault for such an outcome?

wayneftw 5y ago
From my own experience, I see that vaccinated people are less fearful of mixing with large groups of people. That's one way the vaccinated can be more easily infected. It's not a physiological effect but I think it's probably the crux of the whole issue here.
- jonplackett 5y ago
  Behaviour-wise this is definitely true - not for everyone, but many. But I don't think it wouldn't matter for the comparison because they're looking at rates of serious illness, rather than absolute number of people catching it. Saying that, if seriousness of disease is related to initial exposure amount, perhaps being vaxxed and overly brave could mean you get a higher initial dose?
  - wayneftw 5y ago
    OK thanks. I thought the major concern was the number of people getting it not the number of severe cases... I'm not really sure why it is this way. I would think lessening the spread of it would be the highest priority.
recursivedoubts 5y ago
A possible mechanism I have seen mentioned is Antibody Dependent Enhancement: https://en.wikipedia.org/wiki/Antibody-dependent_enhancement https://en.wikipedia.org/wiki/Antibody-dependent_enhancement I am not a biologist and have no opinion on the matter, I have just seen it mentioned online.
- belter 5y ago
  Interesting. It seems that this was actually a concern and considered during initial development of COVID vaccines. It seems it was considered not likely to happen but there is this interesting part here from 2019 that caught my attention: "Consensus summary report for CEPI/BC March 12–13, 2020 meeting: Assessment of risk of disease enhancement with COVID-19 vaccines" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247514/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247514/ "A syndrome of “disease enhancement” has been reported in the past for a few viral vaccines where those immunized suffered increased severity or death when they later encountered the virus or were found to have an increased frequency of infection. Animal models allowed scientists to determine the underlying mechanism for the former in the case of Respiratory syncytial virus (RSV) vaccine and have been utilized to design and screen new RSV vaccine candidates. Because some Middle East respiratory syndrome (MERS) and SARS-CoV-1 vaccines have shown evidence of disease enhancement in some animal models, this is a particular concern for SARS-CoV-2 vaccines. To address this challenge, the Coalition for Epidemic Preparedness Innovations (CEPI) and the Brighton Collaboration (BC) Safety Platform for Emergency vACcines (SPEAC) convened a scientific working meeting on March 12 and 13, 2020 of experts in the field of vaccine immunology and coronaviruses to consider what vaccine designs could reduce safety concerns and how animal models and immunological assessments in early clinical trials can help to assess the risk. This report summarizes the evidence presented and provides considerations for safety assessment of COVID-19 vaccine candidates in accelerated vaccine development."
  - belter 5y ago
    Hopefully somebody will be able to comment further. In the meanwhile...I found this a good quality overview of the issue. Reference includes video and transcript for quicker read. The TL;DR is that is considered unlikely for reasons explained. ( but not completely impossible ) "Do COVID-19 Vaccines Cause Antibody-dependent Enhancement (ADE)?" https://www.chop.edu/centers-programs/vaccine-education-center/video/do-covid-19-vaccines-cause-antibody-dependent-enhancement https://www.chop.edu/centers-programs/vaccine-education-cent...
- polotics 5y ago
  Can someone who knows more than me comment on my impression that the likelihood of ADE is much reduced with the very narrow (ie. spike-only) targeting of mRNA vaccines?
- throwawayboise 5y ago
  ADE can also happen with exposure to a virus itself, such as happens with Dengue fever. It's not something strictly limited to vaccines.
  - belter 5y ago
    Correct. That is also mentioned in the reference with video I posted.
  - higherup 5y ago
    >It's not something strictly limited to vaccines. I think it is the case if the vaccine does not provide sterilising immunity..

From my own experience, I see that vaccinated people are less fearful of mixing with large groups of people. That's one way the vaccinated can be more easily infected. It's not a physiological effect but I think it's probably the crux of the whole issue here.

jonplackett 5y ago
Behaviour-wise this is definitely true - not for everyone, but many. But I don't think it wouldn't matter for the comparison because they're looking at rates of serious illness, rather than absolute number of people catching it. Saying that, if seriousness of disease is related to initial exposure amount, perhaps being vaxxed and overly brave could mean you get a higher initial dose?
- wayneftw 5y ago
  OK thanks. I thought the major concern was the number of people getting it not the number of severe cases... I'm not really sure why it is this way. I would think lessening the spread of it would be the highest priority.

recursivedoubts 5y ago

A possible mechanism I have seen mentioned is Antibody Dependent Enhancement: https://en.wikipedia.org/wiki/Antibody-dependent_enhancement https://en.wikipedia.org/wiki/Antibody-dependent_enhancement I am not a biologist and have no opinion on the matter, I have just seen it mentioned online.

belter 5y ago
Interesting. It seems that this was actually a concern and considered during initial development of COVID vaccines. It seems it was considered not likely to happen but there is this interesting part here from 2019 that caught my attention: "Consensus summary report for CEPI/BC March 12–13, 2020 meeting: Assessment of risk of disease enhancement with COVID-19 vaccines" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247514/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247514/ "A syndrome of “disease enhancement” has been reported in the past for a few viral vaccines where those immunized suffered increased severity or death when they later encountered the virus or were found to have an increased frequency of infection. Animal models allowed scientists to determine the underlying mechanism for the former in the case of Respiratory syncytial virus (RSV) vaccine and have been utilized to design and screen new RSV vaccine candidates. Because some Middle East respiratory syndrome (MERS) and SARS-CoV-1 vaccines have shown evidence of disease enhancement in some animal models, this is a particular concern for SARS-CoV-2 vaccines. To address this challenge, the Coalition for Epidemic Preparedness Innovations (CEPI) and the Brighton Collaboration (BC) Safety Platform for Emergency vACcines (SPEAC) convened a scientific working meeting on March 12 and 13, 2020 of experts in the field of vaccine immunology and coronaviruses to consider what vaccine designs could reduce safety concerns and how animal models and immunological assessments in early clinical trials can help to assess the risk. This report summarizes the evidence presented and provides considerations for safety assessment of COVID-19 vaccine candidates in accelerated vaccine development."
- belter 5y ago
  Hopefully somebody will be able to comment further. In the meanwhile...I found this a good quality overview of the issue. Reference includes video and transcript for quicker read. The TL;DR is that is considered unlikely for reasons explained. ( but not completely impossible ) "Do COVID-19 Vaccines Cause Antibody-dependent Enhancement (ADE)?" https://www.chop.edu/centers-programs/vaccine-education-center/video/do-covid-19-vaccines-cause-antibody-dependent-enhancement https://www.chop.edu/centers-programs/vaccine-education-cent...
polotics 5y ago
Can someone who knows more than me comment on my impression that the likelihood of ADE is much reduced with the very narrow (ie. spike-only) targeting of mRNA vaccines?
throwawayboise 5y ago
ADE can also happen with exposure to a virus itself, such as happens with Dengue fever. It's not something strictly limited to vaccines.
- belter 5y ago
  Correct. That is also mentioned in the reference with video I posted.
- higherup 5y ago
  >It's not something strictly limited to vaccines. I think it is the case if the vaccine does not provide sterilising immunity..