03.16.2021 01:56 PM

No blood clot yet

So, I got the AZ shot. Still alive (sorry, Justin). Column on the safety of AstraZeneca vaccine coming soon.

7 Comments

  1. Murphy's Raw says:

    Good Man.

    I think we were getting our pokes around the same time.

    Looking forward to your upcoming article adding some needed sanity, rational thought and context to the AZ vaccine discussion (or am I hoping for too much?).

  2. Nick Arrizza says:

    I try to follow the facts and so far the facts from AZ have not been very inspiring. First their phase 3 study (ages 18 to 64 only) done in different countries showed that in Brazil where they gave a low dose/standard dose (LD/SD) regimen by accident they got an efficacy rate against mild/moderate COVID to be around 90%. In other settings where they gave SD/SD the efficacy turned out to be only 62% (I still don’t know what the age, ethnicity and co-morbidity specific efficacy are because I can’t find that data anywhere) just barely making the FDA standard. So AZ decided to do a weighted average of these groups and came up with a figure of roughly 70% efficacy which actually is inaccurate because they are not actually giving the LD/SD regimen to the general population only the SD/SD regimen which means that the actual efficacy is only 62% yet they purport that it will be 70%. Next they initially did not test the vaccine in the over 65 age group and only in the last week did they present a pre-print (not yet peer reviewed) of a real world study looking the ‘combined efficacy’ of the Pfizer and AZ vaccine in those over 80 (I could find no data for ages 65 to 80 in this study) with respect to being able to prevent hospitalizations and reported this to be 81% for the ‘pooled’ i.e. averaged data for Pfizer AND AZ vaccines together but not separately which means we don’t know, unless they provide us the data (which the author of this pre-print has yet to respond to my request for) what the separate efficacy rates for each of the 2 vaccines is. What we do know from other sources is that the Pfizer vaccine is actually 97% effective (much higher than the suspiciously quoted 81% ) in preventing hospitalizations so depending on the relative size of the Pfizer & AZ groups studied here if we assume they were say roughly the same size that could potentially mean in order to get a figure of 81% one would have an AZ efficacy rate close to only 60% in order to get an average of 81% for the pooled data! See what I mean? We need the data! So on both occasions AZ seems to have done this “averaging” trick. Finally, with respect to blood clots, some simple research reveals that the majority of blood clots occur in those who are over 60 and less often in the younger population so in order to accurately assess whether AZ vaccine is responsible for the reported clotting incidents what we need to compare is the ‘age/ethnicity/co-morbidity specific blood clot frequencies’ of the clotting incidents to that of the general population age/ethnicity/co-morbidity specific blood clot frequencies and not simply the overall average of the vaccinated and un-vaccinated general population. And again, I would love to see this data but have not been able to find it nor is it anywhere on Health Canada’s site, where I strongly feel it should be so that members of the public can see it for themselves in the same way that the FDA makes all their data explicit. So am I a vaccine conspiracy theorist or anti-vaxer? No! I more than anyone would like to get vaccinated and have my family do the same so that we can get on with our lives BUT I just want to know that the vaccine I am going to take is effective and safe. So far, the jury on this one is not so clear, at least for me. I am asking those who have the data I have cited above to kindly make it public so that we can have only the facts and not conspiracies which will only circulate as long as these facts remain out of sight. Thanks!

    • David Bronaugh says:

      It’s, so far, safer than the Pfizer vaccine, which causes occasional anaphalaxis. It’s also less effective. In my age cohort, that sounds like the right tradeoff. For my mom, who’s over 80, I’d prefer that she get the Pfizer vaccine (or the Moderna), because for *her*, that’s the right tradeoff. It’s also the right thing for *me* to do, to save those Pfizer/Moderna doses for those at the highest risk of death. Pretty simple mathematical calculus to me.

      I’ll be waiting on the vaccine until it’s my turn, as I would at this point be taking that dose away from someone in a higher risk category. That’s my personal ethical calculus.

      • Nick Arrizza says:

        Personally, I would like to see Novavax and Medicago vaccine roll outs ramp up. I would also like to see Health Canada re-purpose Ivermectin for prophylaxis and treatment of COVID-19 and variants as a bridge to when we all can become adequately vaccinated as the BIRD (British Ivermectin Research Development) Committee Recommendations suggest given that we are now being threatened by a third and potentially more deadly wave of variants with still precarious vaccine supplies on the horizon.Take care!

      • Nick Arrizza says:

        Sorry, I just saw this:

        https://www.telegraph.co.uk/global-health/science-and-disease/link-blood-clots-astrazeneca-vaccine-not-implausible-says-german/

        Data from Germany now suggests there may actually be a higher risk of clots with AZ vaccine in some groups as I had voiced in my earlier concerns about looking at age/ethnicity/co-morbidity clot frequencies!

        I’m glad someone is doing their homework!

        • David Bronaugh says:

          Yeah… I am not completely sure of the credibility of that (seems like the jury is still out). But, let me put it in context:
          – About 10k Germans per day are getting Covid, or about 1 per 10k per day (0.00001).
          – In the lowest risk cohort (18-39), your odds of dying from COVID-19 are around 0.06% (0.0006)
          – Thus, in Germany, your daily risk of dying from COVID-19 if you’re in the 18-39 cohort is around 1 in 166 million.
          – The case incidence of this is about 1 per 250k, over 16 days. The risk of death is 1 in 500k.
          – Thus, for the 18-39 cohort, the ROI for getting the AZ vaccine is about 1 year in terms of the risk of death.
          – If no one in the 18-39 risk cohort got vaccinated, covid would continue to run through the population (due to the R0 being high), resulting in a likely rate of cases of at least what we’re currently seeing, especially considering the UK variant.
          – Because of this, the risk calculus, even if you’re in the 18-39 cohort, is clear: you should get the AZ vaccine, if no other vaccine is available.

          It’s not super easy to analyze this, and it’s *probably* better to get a different vaccine if you can, if you’re in that 18-39 cohort. For pretty much every other cohort, the risk calculus is on the side of “get any vaccine”.

          • Nick Arrizza says:

            David, great analysis! Thank you! Only issue is it’s not clear to me exactly who are getting these blood clots. It may not necessarily be only/or age related i.e. it could be a specific sub group such as say young women who are on contraceptives who have some other common characteristics such as ethnicity, co-morbid conditions, etc.. This is the kind sub group analysis I would like to see from the epidemiologists (which BTW should also have been done and communicated early in the pandemic to identify those at highest risk of severe illness and death; which some have done i.e. Dr Neal Barnard who has been educating people in the co-morbid groups about relevant dietary changes to effectively and rapidly reverse these conditions ). If they were able to identify such a subgroup then at least they could alert such individuals to take another vaccine. What I keep hearing instead however are only general averaged (over entire populations) benefit/risk assessments. The recent EMA advice of simply providing a warning in my view is laughable. What is someone supposed to do with that, I wonder? Stay well!

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