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"Of the 10 cases of severe Covid-19, nine were in the placebo group, an important finding which suggests the vaccine prevents not only mild cases, but the type

by hannob 6y ago

"Of the 10 cases of severe Covid-19, nine were in the placebo group, an important finding which suggests the vaccine prevents not only mild cases, but the type of serious disease that leads patients to die or be hospitalized." https://www.statnews.com/2020/11/18/pfizer-biontech-covid19-vaccine-fda-data/ https://www.statnews.com/2020/11/18/pfizer-biontech-covid19-...

usrusr 6y ago
So the distribution amongst vaccinated group cases seems to be roughly the same as on the control group. In my armchair viroligy ponderings I have come to the conclusion that this is the best possible outcome because both directions of possible distribution shifts could be bad news: if all detected vaccinated cases would be hard cases it would indicate that the vaccine has much lower efficacy than stated with those that require the hardest to be saved by a vaccine, whereas an overrepresentation of weak cases would suggest that much more weak cases get through, that the vaccine would not prevent infection very much but only keep an infection from becoming a heavy case (weak cases are very likely to remain undetected in both the vaccinated group and in the control group). A downshift in severity would be just fine for the vaccinated, but with a virus like SARS-COV-2 that is very good at asymptomatic spread it would not contribute much to herd immunity, increasing risk for the non-vaccinated (because the lucky ones would drop all precautions.
ummonk 6y ago
Awesome, thanks! This is really great news.
notatoad 6y ago
if the vaccine is ~90% effective, wouldn't we expect that for any ten random cases in the trial, 9 would be in the placebo group? i don't see how that rate implies anything about the severity of the infection
- ummonk 6y ago
  Ignoring statistical significance for the purposes of this discussion, the observed rate suggests that the vaccine is 90% effective at preventing severe infections as well, not just mild infections. In a worse world it could have been the case that e.g. the vaccine was 90% effective at preventing infections but still had the same number of severe infections because it did nothing to help the most vulnerable patients.

by hannob 6y ago

usrusr 6y ago

So the distribution amongst vaccinated group cases seems to be roughly the same as on the control group. In my armchair viroligy ponderings I have come to the conclusion that this is the best possible outcome because both directions of possible distribution shifts could be bad news: if all detected vaccinated cases would be hard cases it would indicate that the vaccine has much lower efficacy than stated with those that require the hardest to be saved by a vaccine, whereas an overrepresentation of weak cases would suggest that much more weak cases get through, that the vaccine would not prevent infection very much but only keep an infection from becoming a heavy case (weak cases are very likely to remain undetected in both the vaccinated group and in the control group). A downshift in severity would be just fine for the vaccinated, but with a virus like SARS-COV-2 that is very good at asymptomatic spread it would not contribute much to herd immunity, increasing risk for the non-vaccinated (because the lucky ones would drop all precautions.

ummonk 6y ago

Awesome, thanks! This is really great news.

notatoad 6y ago

if the vaccine is ~90% effective, wouldn't we expect that for any ten random cases in the trial, 9 would be in the placebo group? i don't see how that rate implies anything about the severity of the infection

ummonk 6y ago
Ignoring statistical significance for the purposes of this discussion, the observed rate suggests that the vaccine is 90% effective at preventing severe infections as well, not just mild infections. In a worse world it could have been the case that e.g. the vaccine was 90% effective at preventing infections but still had the same number of severe infections because it did nothing to help the most vulnerable patients.