Do these two vaccines (J&J and AstraZeneca) have tPA as an adjuvant?
I could see a scenario in which an over-activated fibrinolytic system could steadily consume platelets leaving a patient thrombocytopenic.
I’m also wondering if recent (possibly asymptomatic) infection with SARS-Cov-2 might be at play? I’m not very familiar with the vascular effects of this virus but I could also see how compromised vessel walls could also consume platelets and simultaneously activate the body’s coagulation system.
No, neither the J&J or AZ vaccines contain any adjuvants. Viral vector vaccines usually do not contain adjuvants because of how closely the vector-borne approach is thought to mimic natural infection and thus stimulate an immune response.
I've wondered also about whether there were SARS-CoV-2 infections in these patients that went undetected. SARS-CoV-2 definitely increases clotting risk, it is well-established as an issue that occurs in COVID-19. I hope we learn more about these cases soon.
As a platelet donor, I selectively notice stuff about thromobocytopenia (and thrombocytes in general). It isn't that uncommon for clotting syndromes to be associated with thrombocytopenia, in at least some cases because suddenly forming a lot of clots removes many platelets from circulation (literally). Note also that COVID-19 seems to be associated with thromobocytopenia in some cases, e. g. https://pubmed.ncbi.nlm.nih.gov/32178975/
You wrote, "All have been between the ages of 18 and 48. Even early in 2020, before many treatment modalities were available, patients in this age range were seen to have a case-fatality rate from COVID-19 that is substantially less than 1%, ranging from about 0.2% in the youngest bracket in this range to 0.4% in the oldest bracket. These risks will be lower now." Contrariwise, the variants like B.1.1.7 seem to be more dangerous for younger patients than the originally-detected strain.
As a critical thinking person, it's interesting watching myself think about this matter. I find myself looking for ways to explain away the J&J/AZ clotting phenomenon, because I really, really want it to not be real. It takes real mental effort to acknowledge one's own bias and force oneself to follow the evidence.
It's true that there can be a drop in platelet counts during major clotting events, but it's not usually so extreme as what was seen in these patients. Specifically, it's not usually so extreme as to make heparin contraindicated for fear of worsening the thrombocytopenia.
That's a good point about B.1.1.7, and I have also heard that it is having bigger impacts on younger populations. I'm just not entirely certain if that's a change in mortality risk or if it's a change in absolute numbers of deaths due to an increase in overall infections with that lineage vs ancestral ones. The epidemiology of B.1.1.7 is full of conflicting information, with some studies saying it has no impact on case fatality rate and others saying it has quite large impacts on CFR. Without a clear scientific consensus I am not sure what to say.
I have to echo your feelings about this clotting situation. I also want it to be some random thing that is not vaccine associated. However, the more I learn about it the more it looks like it could be caused by these vaccines--although I must emphasize that it is still very rare and most people who have received them should not be concerned about this. It's hard to want to be a good vaccine advocate and also talk about a vaccine safety issue. It feels like undermining the cause of vaccination, but the fact is, we do have to follow the evidence because that is what makes vaccines so great--they are evidence-supported tools and they are only approved because there is evidence that their benefits far outweigh their risks. When we are faced with the possibility of a safety issue, taking is seriously and being cautious is vital because it establishes the credibility of the evidence-based approach that forms the foundation for vaccine development and deployment. Or at least, that's the hypothesis I'm operating on.
Hi John,
Do these two vaccines (J&J and AstraZeneca) have tPA as an adjuvant?
I could see a scenario in which an over-activated fibrinolytic system could steadily consume platelets leaving a patient thrombocytopenic.
I’m also wondering if recent (possibly asymptomatic) infection with SARS-Cov-2 might be at play? I’m not very familiar with the vascular effects of this virus but I could also see how compromised vessel walls could also consume platelets and simultaneously activate the body’s coagulation system.
No, neither the J&J or AZ vaccines contain any adjuvants. Viral vector vaccines usually do not contain adjuvants because of how closely the vector-borne approach is thought to mimic natural infection and thus stimulate an immune response.
I've wondered also about whether there were SARS-CoV-2 infections in these patients that went undetected. SARS-CoV-2 definitely increases clotting risk, it is well-established as an issue that occurs in COVID-19. I hope we learn more about these cases soon.
Hi, John,
As a platelet donor, I selectively notice stuff about thromobocytopenia (and thrombocytes in general). It isn't that uncommon for clotting syndromes to be associated with thrombocytopenia, in at least some cases because suddenly forming a lot of clots removes many platelets from circulation (literally). Note also that COVID-19 seems to be associated with thromobocytopenia in some cases, e. g. https://pubmed.ncbi.nlm.nih.gov/32178975/
You wrote, "All have been between the ages of 18 and 48. Even early in 2020, before many treatment modalities were available, patients in this age range were seen to have a case-fatality rate from COVID-19 that is substantially less than 1%, ranging from about 0.2% in the youngest bracket in this range to 0.4% in the oldest bracket. These risks will be lower now." Contrariwise, the variants like B.1.1.7 seem to be more dangerous for younger patients than the originally-detected strain.
As a critical thinking person, it's interesting watching myself think about this matter. I find myself looking for ways to explain away the J&J/AZ clotting phenomenon, because I really, really want it to not be real. It takes real mental effort to acknowledge one's own bias and force oneself to follow the evidence.
It's true that there can be a drop in platelet counts during major clotting events, but it's not usually so extreme as what was seen in these patients. Specifically, it's not usually so extreme as to make heparin contraindicated for fear of worsening the thrombocytopenia.
That's a good point about B.1.1.7, and I have also heard that it is having bigger impacts on younger populations. I'm just not entirely certain if that's a change in mortality risk or if it's a change in absolute numbers of deaths due to an increase in overall infections with that lineage vs ancestral ones. The epidemiology of B.1.1.7 is full of conflicting information, with some studies saying it has no impact on case fatality rate and others saying it has quite large impacts on CFR. Without a clear scientific consensus I am not sure what to say.
I have to echo your feelings about this clotting situation. I also want it to be some random thing that is not vaccine associated. However, the more I learn about it the more it looks like it could be caused by these vaccines--although I must emphasize that it is still very rare and most people who have received them should not be concerned about this. It's hard to want to be a good vaccine advocate and also talk about a vaccine safety issue. It feels like undermining the cause of vaccination, but the fact is, we do have to follow the evidence because that is what makes vaccines so great--they are evidence-supported tools and they are only approved because there is evidence that their benefits far outweigh their risks. When we are faced with the possibility of a safety issue, taking is seriously and being cautious is vital because it establishes the credibility of the evidence-based approach that forms the foundation for vaccine development and deployment. Or at least, that's the hypothesis I'm operating on.