4 ms·

Am I correct in reading this that the Pfizer vaccine was associated with fewer serious side effects (as defined) than the Moderna _placebo_? It seems plausible

Am I correct in reading this that the Pfizer vaccine was associated with fewer serious side effects (as defined) than the Moderna _placebo_? It seems plausible that both vaccines cause slightly more serious side effects than their corresponding placebos (30–60% more if I understand correctly), but it's hard to know how meaningful this result is when one of the placebos is 2.5x more 'dangerous' than the other placebo.

deleted 4y ago
[deleted]
PragmaticPulp 4y ago
> Am I correct in reading this that the Pfizer vaccine was associated with fewer serious side effects (as defined) than the Moderna _placebo_? Given the small differences and wide confidence intervals, the correct interpretation is that the incidence of side effects isn’t really significantly different than placebo. Or you could look at the numbers and decide that given the noise of the data that a massively larger study (10-100X more people) would be necessary to discover any practical differences, should they exist.
vannevar 4y ago
Not according to this part of the result: "The Pfizer trial exhibited a 36 % higher risk of serious adverse events in the vaccine group; risk difference 18.0 per 10,000 vaccinated (95 % CI 1.2 to 34.9); risk ratio 1.36 (95 % CI 1.02 to 1.83). The Moderna trial exhibited a 6 % higher risk of serious adverse events in the vaccine group: risk difference 7.1 per 10,000 (95 % CI -23.2 to 37.4); risk ratio 1.06 (95 % CI 0.84 to 1.33)." This seems to contradict the first sentence, which implies Moderna is worse: "Pfizer and Moderna mRNA COVID-19 vaccines were associated with an excess risk of serious adverse events of special interest of 10.1 and 15.1 per 10,000 vaccinated over placebo baselines of 17.6 and 42.2 (95 % CI -0.4 to 20.6 and -3.6 to 33.8), respectively." I'm not sure how to reconcile the apparent contradiction, perhaps others understand what's being said?
- EGreg 4y ago
  What it’s saying is that in both cases the unvaccinated group had less risk from not taking the vaccine than taking it. The placebo isn’t relevant, just the fact they didn’t take the vaccine. Since it’s randomized, it’s unsurprising that both groups of unvaccinated people had diff risk outcomes. What IS surprising is that the vaccine performed worse than both random groups of unvaccinated people.
  - vannevar 4y ago
    >What it’s saying is that in both cases the unvaccinated group had less risk from not taking the vaccine than taking it. I get that, but why is the quantitative description of the risk different in the first sentence than it is later in the paragraph? The first sentence clearly indicates that the risk is higher with Moderna (excess risk of 15.1 vs 10.1 per 10,000), while later the excess risk of Pfizer is stated as 18.0 per 10,000, while Moderna's is a much lower 7.1 per 10,000. I assume the numbers describe different things, but it isn't clear what the difference is.
    - yakak 4y ago
      These two studies are not normalized on time so slightly more events in ~two months for A vs B verse a lot more in ~one month for C vs D means more total events in A than C. Really, if you believe the primary difference is that pfizer was a lower dose and that this isn't all just noise, the data seems to be showing that there's a pretty short window where the risk of the jab wasn't made up for by benefit such that a longer study lost ground on finding a measurable risk.

deleted 4y ago

[deleted]

PragmaticPulp 4y ago

> Am I correct in reading this that the Pfizer vaccine was associated with fewer serious side effects (as defined) than the Moderna _placebo_? Given the small differences and wide confidence intervals, the correct interpretation is that the incidence of side effects isn’t really significantly different than placebo. Or you could look at the numbers and decide that given the noise of the data that a massively larger study (10-100X more people) would be necessary to discover any practical differences, should they exist.

vannevar 4y ago

Not according to this part of the result: "The Pfizer trial exhibited a 36 % higher risk of serious adverse events in the vaccine group; risk difference 18.0 per 10,000 vaccinated (95 % CI 1.2 to 34.9); risk ratio 1.36 (95 % CI 1.02 to 1.83). The Moderna trial exhibited a 6 % higher risk of serious adverse events in the vaccine group: risk difference 7.1 per 10,000 (95 % CI -23.2 to 37.4); risk ratio 1.06 (95 % CI 0.84 to 1.33)." This seems to contradict the first sentence, which implies Moderna is worse: "Pfizer and Moderna mRNA COVID-19 vaccines were associated with an excess risk of serious adverse events of special interest of 10.1 and 15.1 per 10,000 vaccinated over placebo baselines of 17.6 and 42.2 (95 % CI -0.4 to 20.6 and -3.6 to 33.8), respectively." I'm not sure how to reconcile the apparent contradiction, perhaps others understand what's being said?

EGreg 4y ago
What it’s saying is that in both cases the unvaccinated group had less risk from not taking the vaccine than taking it. The placebo isn’t relevant, just the fact they didn’t take the vaccine. Since it’s randomized, it’s unsurprising that both groups of unvaccinated people had diff risk outcomes. What IS surprising is that the vaccine performed worse than both random groups of unvaccinated people.
- vannevar 4y ago
  >What it’s saying is that in both cases the unvaccinated group had less risk from not taking the vaccine than taking it. I get that, but why is the quantitative description of the risk different in the first sentence than it is later in the paragraph? The first sentence clearly indicates that the risk is higher with Moderna (excess risk of 15.1 vs 10.1 per 10,000), while later the excess risk of Pfizer is stated as 18.0 per 10,000, while Moderna's is a much lower 7.1 per 10,000. I assume the numbers describe different things, but it isn't clear what the difference is.
  - yakak 4y ago
    These two studies are not normalized on time so slightly more events in ~two months for A vs B verse a lot more in ~one month for C vs D means more total events in A than C. Really, if you believe the primary difference is that pfizer was a lower dose and that this isn't all just noise, the data seems to be showing that there's a pretty short window where the risk of the jab wasn't made up for by benefit such that a longer study lost ground on finding a measurable risk.