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The biggest flaw with this study is that it does not account for prior natural infection. It has been thoroughly demonstrated that individuals who acquire immun

The biggest flaw with this study is that it does not account for prior natural infection. It has been thoroughly demonstrated that individuals who acquire immunity through natural infection have a robust and durable immune response [1][2][3]. Recent vaccination on top of this immunity is likely to further prime and improve immune responses to subsequent infection [4][5]. Not accounting for this fact is a significant confounding factor in the study, and I'm disappointed the authors made no distinction between unvaccinated and immunologically naive. This is a distinction that every sensible scientific discussion needs to acknowledge. EDIT: please leave a comment down voters, I’m starting to think there’s some sort of targeted campaign against this type of information > Vaccine breakthrough infections exhibited similar proliferation dynamics as infections in unvaccinated individuals (mean peak Ct: 20.5, 95% credible interval [19.0, 21.0] vs. 20.7 [19.8, 20.2], and mean proliferation time 3.2 days[2.5, 4.0] vs. 3.5 days [3.0, 4.0]); however, vaccinated individuals exhibited faster clearance (mean clearance time: 5.5 days [4.6, 6.6] vs. 7.5 days [6.8, 8.2]). > If the Ct values in vaccinated and unvaccinated infected individuals reflect the same amounts of infectious virus, then this implies that individuals with breakthrough infections may be as infectious as unvaccinated individuals in the early stage of the infection, but remain infectious for a shorter time, reducing the total degree of onward transmission. These findings are in keeping with the hypothesis that vaccination protects against the severe manifestations of disease but offers less protection against infection in the upper airway. Precautions are therefore necessary to prevent onward transmission even from vaccinated individuals. [1] Longitudinal analysis shows durable and broad immune memory after SARS-CoV-2 infection with persisting antibody responses and memory B and T cells https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(21)00203-2 https://www.cell.com/cell-reports-medicine/fulltext/S2666-37... [2] SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN) https://pubmed.ncbi.nlm.nih.gov/33844963/ https://pubmed.ncbi.nlm.nih.gov/33844963/ [3] Association of SARS-CoV-2 Seropositive Antibody Test With Risk of Future Infection https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2776810 https://jamanetwork.com/journals/jamainternalmedicine/fullar... [4] Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection https://www.nature.com/articles/s41586-021-03696-9 https://www.nature.com/articles/s41586-021-03696-9 [5] Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine https://www.nature.com/articles/s41591-021-01316-7 https://www.nature.com/articles/s41591-021-01316-7

walterbell 5y ago
> authors made no distinction between unvaccinated and immunologically naive. This is a distinction that every sensible scientific discussion needs to acknowledge. Ideally, everyone would be tested for antibodies before receiving a vaccine, then we would have data to differentiate naive+vaccine from survivor+vaccine. This would be helpful for both science and public policy. CDC needs to stop labelling people who are 13 days after their 2nd vaccine dose as "unvaccinated". A more accurate label would be "partly vaccinated".
- criticaltinker 5y ago
  > Ideally, everyone would be tested for antibodies before receiving a vaccine I agree that would help make optimal decisions with regards to distributing a limited supply of vaccine doses. However it's worth noting that even when antibodies drop below levels detectable by standard tests, individuals are likely to retain robust immune responses that provide sufficient protection from severe outcomes [1][2]. [1] SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans https://www.nature.com/articles/s41586-021-03647-4.pdf https://www.nature.com/articles/s41586-021-03647-4.pdf [2] Prior COVID-19 protects against reinfection, even in the absence of detectable antibodies https://www.journalofinfection.com/article/S0163-4453(21)00266-8/fulltext https://www.journalofinfection.com/article/S0163-4453(21)002...
  - walterbell 5y ago
    Does this mean there's a narrow testing window for people to be able to "prove" their natural immunity?
    - criticaltinker 5y ago
      The window for SARS-CoV-2 antibody tests would be at least 8 months to a year for many individuals. More expensive tests can detect immunity based on T cells for example, which would provide an even longer window. And of course really expensive and invasive bone marrow aspirate tests could provide a window approaching a lifetime - but the tradeoffs involved there would likely be unfavorable for practical “proof”. Who knows what technology we’ll come up with in the future though.

walterbell 5y ago

> authors made no distinction between unvaccinated and immunologically naive. This is a distinction that every sensible scientific discussion needs to acknowledge. Ideally, everyone would be tested for antibodies before receiving a vaccine, then we would have data to differentiate naive+vaccine from survivor+vaccine. This would be helpful for both science and public policy. CDC needs to stop labelling people who are 13 days after their 2nd vaccine dose as "unvaccinated". A more accurate label would be "partly vaccinated".

criticaltinker 5y ago
> Ideally, everyone would be tested for antibodies before receiving a vaccine I agree that would help make optimal decisions with regards to distributing a limited supply of vaccine doses. However it's worth noting that even when antibodies drop below levels detectable by standard tests, individuals are likely to retain robust immune responses that provide sufficient protection from severe outcomes [1][2]. [1] SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans https://www.nature.com/articles/s41586-021-03647-4.pdf https://www.nature.com/articles/s41586-021-03647-4.pdf [2] Prior COVID-19 protects against reinfection, even in the absence of detectable antibodies https://www.journalofinfection.com/article/S0163-4453(21)00266-8/fulltext https://www.journalofinfection.com/article/S0163-4453(21)002...
- walterbell 5y ago
  Does this mean there's a narrow testing window for people to be able to "prove" their natural immunity?
  - criticaltinker 5y ago
    The window for SARS-CoV-2 antibody tests would be at least 8 months to a year for many individuals. More expensive tests can detect immunity based on T cells for example, which would provide an even longer window. And of course really expensive and invasive bone marrow aspirate tests could provide a window approaching a lifetime - but the tradeoffs involved there would likely be unfavorable for practical “proof”. Who knows what technology we’ll come up with in the future though.