5 ms·

For people misled by the headline: No new issues seem to have been discovered; the article just seems to explain why some study participants received a half dos

For people misled by the headline: No new issues seem to have been discovered; the article just seems to explain why some study participants received a half dose (which was already reported and actually turned out to likely be _more_ effective than the full dose).

rebuilder 6y ago
The article says more than that: "Some experts say the dosing discrepancy raises doubts about the robustness of the study’s findings. And they worry about another acknowledged peculiarity of the study: The half-dose regimen wasn’t tested on anyone over 55 - the group considered at high risk from COVID-19."
- randcraw 6y ago
  Exactly. When you remove the patient group that experiences 90% of the severe cases, voila, your efficacy rate skyrockets. Until SOMEONE ELSE completes trials on that missing age 55+ cohort, this vaccine should be accepted ONLY for ages 0 to 54. And given its likely low efficacy (62%), NOT for anyone with co-morbidities.
  - happymellon 6y ago
    This statement is moronic. The vaccine has been tested on 55+. We are not doing a half initial dose because that hasn't been studied in detail.
  - DanBC 6y ago
    > patient group that experiences 90% of the severe cases, 43% of the patients going into ICUs in the UK[1] are under 60 years old. Most of the patients going into ICUs (including the older people) needed no assistance in their day to day lives before going into ICU.
    - Engineering-MD 6y ago
      But that is also a selection bias. The very elderly or those who need lots of assistance in day to day lives or those with multiple comorbidities are much less likely to benefit from an ICU stay (ie they will likely die with or without support) so don’t get admitted at all.
- happymellon 6y ago
  Which is why we are not going to use the half dose. 60% efficiency which has been peer reviewed, is still as good as the flu vaccine, it can be stored in a normal fridge so will work better for distribution outside of major cities, and costs significantly less. There are very few downsides, apart from not generating American news.
  - addicted 6y ago
    There aren’t many downsides at the moment because the safety is probably pretty ok and the efficacy is probably pretty decent, but the reality is that AstraZeneca completely botched their study and if this was not basically an emergency situation, the vaccine would not have been approved.
    - MrAlex94 6y ago
      AstraZeneca did not conduct the study, Oxford did from the looks of it in relation to the half dose. The independent regulator was aware at every stage and recommended they continue with trying the half dose trial. [1](https://www.bbc.co.uk/news/health-55308216 https://www.bbc.co.uk/news/health-55308216).
  - throwaway2245 6y ago
    Doesn't 50% efficacy, by this measure, mean it has no effect at all? By my understanding, the quoted figure is what percentage of infection occurred in the control group. 60% efficacy is not going to get you to herd immunity, nor even any kind of immunity for the majority of people taking the vaccine.
    - FuckButtons 6y ago
      No, it means that you reduce risk by 60%, the threshold for efficacy that government agencies were looking at was around 30% so it’s definitely effective, just less so than the rna vaccines.
      - throwaway2245 6y ago
addicted 6y ago
The half dose being more effective than the full one is a potential red flag that the study results are off.
- IgorPartola 6y ago
  From what I read it’s a lot more complex than that. One theory is that it’s due to how the AZ vaccine is constructed. It is a neutered chimp adenovirus that cannot reproduce but is able to infect cells and cause them to produce the COVID spike protein that the immune system can detect and react to. So it is a two stage process: infect the cell, make it produce the spike protein, have the spike protein attach to another cell, and finally have the immune system respond to the spike protein. The idea is that if you inject too high a dose initially, the immune system will instead respond to the adenovirus and kill it before it can carry out its intended job here. Having a slower initial response will allow for enough COVID spike protein to be produced to develop an immunity to that. I am absolutely not an expert on this. Just paraphrasing something I read.
  - Exmoor 6y ago
    That's accurate. It was a known concern going into the trials. Enough so that the Russian Sputnik V vaccine purposely used a different adenovirus in the first dose and the second dose and appears to have about 92% efficacy rate. I believe Oxford is also planning on running a trial using a mix of the Oxford and Spuknik vaccines to see if it improves efficacy.
- ulfw 6y ago
  The fact it was an error and they can't really explain why it's better, but have some ideas why it could be, is a red flag.
- athriren 6y ago
  the immune system is where intuition goes to die and it is not uncommon for lower potency vaccines to provoke more effective immune responses. i do agree oxford and astrazeneca have not handled this well. it seems quite clearly an error based on a volume of documentation but leadership at both institutions appear to be insisting it was not, which degrades trust at a time when many members of the public do not trust health officials to tell them which way is up.

rebuilder 6y ago

The article says more than that: "Some experts say the dosing discrepancy raises doubts about the robustness of the study’s findings. And they worry about another acknowledged peculiarity of the study: The half-dose regimen wasn’t tested on anyone over 55 - the group considered at high risk from COVID-19."

randcraw 6y ago
Exactly. When you remove the patient group that experiences 90% of the severe cases, voila, your efficacy rate skyrockets. Until SOMEONE ELSE completes trials on that missing age 55+ cohort, this vaccine should be accepted ONLY for ages 0 to 54. And given its likely low efficacy (62%), NOT for anyone with co-morbidities.
- happymellon 6y ago
  This statement is moronic. The vaccine has been tested on 55+. We are not doing a half initial dose because that hasn't been studied in detail.
- DanBC 6y ago
  > patient group that experiences 90% of the severe cases, 43% of the patients going into ICUs in the UK[1] are under 60 years old. Most of the patients going into ICUs (including the older people) needed no assistance in their day to day lives before going into ICU.
  - Engineering-MD 6y ago
    But that is also a selection bias. The very elderly or those who need lots of assistance in day to day lives or those with multiple comorbidities are much less likely to benefit from an ICU stay (ie they will likely die with or without support) so don’t get admitted at all.
happymellon 6y ago
Which is why we are not going to use the half dose. 60% efficiency which has been peer reviewed, is still as good as the flu vaccine, it can be stored in a normal fridge so will work better for distribution outside of major cities, and costs significantly less. There are very few downsides, apart from not generating American news.
- addicted 6y ago
  There aren’t many downsides at the moment because the safety is probably pretty ok and the efficacy is probably pretty decent, but the reality is that AstraZeneca completely botched their study and if this was not basically an emergency situation, the vaccine would not have been approved.
  - MrAlex94 6y ago
    AstraZeneca did not conduct the study, Oxford did from the looks of it in relation to the half dose. The independent regulator was aware at every stage and recommended they continue with trying the half dose trial. [1](https://www.bbc.co.uk/news/health-55308216 https://www.bbc.co.uk/news/health-55308216).
- throwaway2245 6y ago
  Doesn't 50% efficacy, by this measure, mean it has no effect at all? By my understanding, the quoted figure is what percentage of infection occurred in the control group. 60% efficacy is not going to get you to herd immunity, nor even any kind of immunity for the majority of people taking the vaccine.
  - FuckButtons 6y ago
    No, it means that you reduce risk by 60%, the threshold for efficacy that government agencies were looking at was around 30% so it’s definitely effective, just less so than the rna vaccines.
    - throwaway2245 6y ago

addicted 6y ago

The half dose being more effective than the full one is a potential red flag that the study results are off.

IgorPartola 6y ago
From what I read it’s a lot more complex than that. One theory is that it’s due to how the AZ vaccine is constructed. It is a neutered chimp adenovirus that cannot reproduce but is able to infect cells and cause them to produce the COVID spike protein that the immune system can detect and react to. So it is a two stage process: infect the cell, make it produce the spike protein, have the spike protein attach to another cell, and finally have the immune system respond to the spike protein. The idea is that if you inject too high a dose initially, the immune system will instead respond to the adenovirus and kill it before it can carry out its intended job here. Having a slower initial response will allow for enough COVID spike protein to be produced to develop an immunity to that. I am absolutely not an expert on this. Just paraphrasing something I read.
- Exmoor 6y ago
  That's accurate. It was a known concern going into the trials. Enough so that the Russian Sputnik V vaccine purposely used a different adenovirus in the first dose and the second dose and appears to have about 92% efficacy rate. I believe Oxford is also planning on running a trial using a mix of the Oxford and Spuknik vaccines to see if it improves efficacy.
ulfw 6y ago
The fact it was an error and they can't really explain why it's better, but have some ideas why it could be, is a red flag.
athriren 6y ago
the immune system is where intuition goes to die and it is not uncommon for lower potency vaccines to provoke more effective immune responses. i do agree oxford and astrazeneca have not handled this well. it seems quite clearly an error based on a volume of documentation but leadership at both institutions appear to be insisting it was not, which degrades trust at a time when many members of the public do not trust health officials to tell them which way is up.