6 ms·

We do not know for sure the 1 dose is highly effective. There's significant real-world data from Israel suggesting the reverse for the Pfizer vaccine (linked to

by yyyk 6y ago

We do not know for sure the 1 dose is highly effective. There's significant real-world data from Israel suggesting the reverse for the Pfizer vaccine (linked to some in my other comment in this topic), and since it's very similar to Moderna's the results may well transfer.

mlyle 6y ago
I strongly disagree. e.g. in the Pfizer trial, during the entire time period from dose 1 to dose 2 VE was 52.4% (95% CI 29.5, 68.4) and almost the entirety of infections happened in the first 10 days; maximum likelihood efficacy rises to 90% if you look at days 10..21. And, of course, there's figure 13. https://i.imgur.com/wEcClPr.png https://i.imgur.com/wEcClPr.png I think the Israel data is being misinterpreted. Your likelihood of being hospitalized 15 days after the vaccine is not affected much, because you were probably exposed between a few days before to a few days after the first dose. And as pointed out-- there's an obvious confound: people may rush out and partay after getting their first dose in the days before protection starts to kick in.
- yyyk 6y ago
  [EDIT: this was written before I saw the OP's edit] There's a trial and there's real world data, and real-world data is eventually more important. Current real-world data in Israel does not indicate good 1st dose efficiency [0]. It's possible the detailed release of the Clalit data [1] will change our 1st dose picture, but judging by the fact they still demand a 2 dose regiment, I suspect that Clalit data shows the same result. A theory is that the Pfizer data was accurate for the 'vanilla' virus, but 1st dose isn't enough for the B117 variant [2], and that's why the 1st dose efficiency was disappointing. [0] https://twitter.com/dvir_a/status/1359603522581454856 https://twitter.com/dvir_a/status/1359603522581454856 [1] https://www.jpost.com/health-science/clalit-data-pfizer-vaccine-reduces-risk-of-serious-covid-19-658959 https://www.jpost.com/health-science/clalit-data-pfizer-vacc... [2] https://twitter.com/AArgoetti/status/1359994165979983873 https://twitter.com/AArgoetti/status/1359994165979983873 [EDIT following OP's edit: Well, it's possible the data was misinterpreted, but there was a statistical attempt to attune for these effects, and antibody tests seem to give a plausible theory for why 1st dose was effective in trials but not real world. Even if you disagree, it's enough of a substantial objection that we can't say we know for sure 1st dose is enough.]
  - mlyle 6y ago
    > but there was a statistical attempt to attune for these effects Can you please explain how the statistical attempt to adjust for latency of "hospitalization" at days 14-21 post-vaccination would have taken place? I believe almost all people hospitalized at days 14-21 would have been infected at times we don't expect the vaccine to be effective from the trial data-- so seeing efficacy near 0 against hospitalization at days 14-21 is indeed exactly what we'd expect. Surely if the vaccine is preventing hospitalization right after the second dose, it prevented infection some time before that, right?? Edit: Observational data is always a mess. This looks particularly bad. Efficacy is higher in the old than in the young?? This is opposite of what we saw in the RCTs. Evidence of massive betas even right after vaccination when we expect efficacy to be 0?? This effectively says the vaccinated group is nothing like the unvaccinated group.
    - yyyk 6y ago
      I believe estimate of infection date is by MOH data, which tries to estimate infection date in patients by clinical data. As for other effects, the idea is to "present the full range of reasonable scenarios and show how they affect the estimation of effectiveness."[0]. I'm not saying the analysis is right (I lack the credentials to say that) but I can tell you Israeli HMOs have been disappointed by 1st dose efficiency and have been vocal about it in media. Soon there'll be a published preprint by Clalit alongside Miguel Hernán and Marc Lipsitch (so not some Israeli-only effort, there's external review), and that is likely to be definitive. For now, Clalit is keeping a 2 dose regiment and applying no pressure to change it. [0] https://twitter.com/dvir_a/status/1357653038354292737 https://twitter.com/dvir_a/status/1357653038354292737
      - mlyle 6y ago
        > I believe estimate of infection date is by MOH data, which tries to estimate infection date in patients by clinical data. I'm reading the methodology PDF and there appears to be no effort to correct for infection date. edit: Examining the MOH data-- the date of first positive test result is used for infections, and the date of hospitalization is used for hospitalization.

by yyyk 6y ago

mlyle 6y ago

I strongly disagree. e.g. in the Pfizer trial, during the entire time period from dose 1 to dose 2 VE was 52.4% (95% CI 29.5, 68.4) and almost the entirety of infections happened in the first 10 days; maximum likelihood efficacy rises to 90% if you look at days 10..21. And, of course, there's figure 13. https://i.imgur.com/wEcClPr.png https://i.imgur.com/wEcClPr.png I think the Israel data is being misinterpreted. Your likelihood of being hospitalized 15 days after the vaccine is not affected much, because you were probably exposed between a few days before to a few days after the first dose. And as pointed out-- there's an obvious confound: people may rush out and partay after getting their first dose in the days before protection starts to kick in.

yyyk 6y ago
[EDIT: this was written before I saw the OP's edit] There's a trial and there's real world data, and real-world data is eventually more important. Current real-world data in Israel does not indicate good 1st dose efficiency [0]. It's possible the detailed release of the Clalit data [1] will change our 1st dose picture, but judging by the fact they still demand a 2 dose regiment, I suspect that Clalit data shows the same result. A theory is that the Pfizer data was accurate for the 'vanilla' virus, but 1st dose isn't enough for the B117 variant [2], and that's why the 1st dose efficiency was disappointing. [0] https://twitter.com/dvir_a/status/1359603522581454856 https://twitter.com/dvir_a/status/1359603522581454856 [1] https://www.jpost.com/health-science/clalit-data-pfizer-vaccine-reduces-risk-of-serious-covid-19-658959 https://www.jpost.com/health-science/clalit-data-pfizer-vacc... [2] https://twitter.com/AArgoetti/status/1359994165979983873 https://twitter.com/AArgoetti/status/1359994165979983873 [EDIT following OP's edit: Well, it's possible the data was misinterpreted, but there was a statistical attempt to attune for these effects, and antibody tests seem to give a plausible theory for why 1st dose was effective in trials but not real world. Even if you disagree, it's enough of a substantial objection that we can't say we know for sure 1st dose is enough.]
- mlyle 6y ago
  > but there was a statistical attempt to attune for these effects Can you please explain how the statistical attempt to adjust for latency of "hospitalization" at days 14-21 post-vaccination would have taken place? I believe almost all people hospitalized at days 14-21 would have been infected at times we don't expect the vaccine to be effective from the trial data-- so seeing efficacy near 0 against hospitalization at days 14-21 is indeed exactly what we'd expect. Surely if the vaccine is preventing hospitalization right after the second dose, it prevented infection some time before that, right?? Edit: Observational data is always a mess. This looks particularly bad. Efficacy is higher in the old than in the young?? This is opposite of what we saw in the RCTs. Evidence of massive betas even right after vaccination when we expect efficacy to be 0?? This effectively says the vaccinated group is nothing like the unvaccinated group.
  - yyyk 6y ago
    I believe estimate of infection date is by MOH data, which tries to estimate infection date in patients by clinical data. As for other effects, the idea is to "present the full range of reasonable scenarios and show how they affect the estimation of effectiveness."[0]. I'm not saying the analysis is right (I lack the credentials to say that) but I can tell you Israeli HMOs have been disappointed by 1st dose efficiency and have been vocal about it in media. Soon there'll be a published preprint by Clalit alongside Miguel Hernán and Marc Lipsitch (so not some Israeli-only effort, there's external review), and that is likely to be definitive. For now, Clalit is keeping a 2 dose regiment and applying no pressure to change it. [0] https://twitter.com/dvir_a/status/1357653038354292737 https://twitter.com/dvir_a/status/1357653038354292737
    - mlyle 6y ago
      > I believe estimate of infection date is by MOH data, which tries to estimate infection date in patients by clinical data. I'm reading the methodology PDF and there appears to be no effort to correct for infection date. edit: Examining the MOH data-- the date of first positive test result is used for infections, and the date of hospitalization is used for hospitalization.