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You have to be careful how you read that. The researchers did not find that the shingles vaccine does not protect men (from dementia caused by Alzheimer's). The

You have to be careful how you read that. The researchers did not find that the shingles vaccine does not protect men (from dementia caused by Alzheimer's). They failed to find statistically significant evidence, in their studied population, that the vaccine protects men. As the preceding sentence says, this can be plausibly explained by the fact that shingles is more common in women, so whatever protective effect the vaccine has is larger and more measurable.

A_D_E_P_T 3y ago
The paper found absolutely no effect in men. That is to say: No trend nor indication that it might protect men. Sometimes trends seem suggestive of a real effect, but don't rise to statistical significance. That is not the case here. This is in Figure 4 of the preprint.
- regularfry 3y ago
  It could also be that there is a potential effect that this study would have been underpowered to detect, and by chance no trend was visible in this population. That's not inconsistent, or even particularly unlikely, if I'm understanding it right.
  - A_D_E_P_T 3y ago
    (A) To suggest that the lack of effect in men is a statistical anomaly, and that there IS an effect we're not seeing. (B) To suggest that the effect in women is a statistical anomaly, and that there's nothing there but a fluke. These things, from the data, are approximately equally likely. Because there was zero effect in men -- in fact, men who took the vaccine were apparently more likely to be diagnosed with Alzheimer's, though this trend was extremely slight.
    - adgjlsfhk1 3y ago
      this isn't necessarily true. if the study had 1000 women and 100 men, it would be a lot more likely that the result in men was wrong. similarly, if the effect was 20x weaker in men than women, but still existed you would be much more likely to see no effect in men even though effects existed for both.
      - A_D_E_P_T 3y ago
        Not necessarily true in a theoretical sense, sure. But there's absolutely no indication that they enrolled 10x (or even 2x) more women than men. Nor is there any indication of any effect in men, 20x weaker or otherwise. (If we're charitable, it's pretty much a flat zero.)
      - sbierwagen 3y ago
        Total study size was 282,541 people, 128,322 men and 154,218 women. From supplementary material 1, page 27: https://www.medrxiv.org/content/10.1101/2023.05.23.23290253v1.supplementary-material https://www.medrxiv.org/content/10.1101/2023.05.23.23290253v...
    - shkkmo 3y ago
      > These things, from the data, are approximately equally likely. They aren't. The paper states that 95% confidence interval for men includes a maximum protective effect of up to -1.9 while the 95% confidence for women include a minimum effect of -1.3. Thus it is far more likely that there is a protective effect for man than no protective effect for women.
      - A_D_E_P_T 3y ago
        Are you ignoring the fact that it might have a negative effect, rather than a protective effect? The range for men is -1.9 to +2.1 -- which averages out to +0.2 -- which indeed makes it seem as though the vaccine's trend is to make one slightly more susceptible to Alzheimer's, rather than less susceptible, which is itself borne out in the figure's trend line. (Fig 4.) For women it's -5.3 to -1.3.
        lamontcg 3y ago
        That means there's a decent chance that the real effect in men is in the range e.g. [-1.9, -1.0] but this study was unlucky or underpowered in men to see that effect.
        Imnimo 3y ago
        Doesn't this mean that the chance of a true but unobserved -1.9 magnitude effect in men is much greater than the chance of a true but unobserved +0.0 magnitude effect in women?
        A_D_E_P_T 3y ago
        Sure, but, by the same token, it also means that there's a chance of a true but unobserved +2 magnitude effect in men.
        shkkmo 3y ago
        >Are you ignoring the fact that it might have a negative effect, rather than a protective effect? Nope. We can be 95% confident that there is an effect for women but we can't be 95% certain that there is no effect for men. Given that the error ranges overlap, we don't even have a high level of certainty that the effect for men doesn't equal the effect for women. > The range for men is -1.9 to +2.1 -- which averages out to +0.2 Technically it averages out as +0.1

A_D_E_P_T 3y ago

The paper found absolutely no effect in men. That is to say: No trend nor indication that it might protect men. Sometimes trends seem suggestive of a real effect, but don't rise to statistical significance. That is not the case here. This is in Figure 4 of the preprint.

regularfry 3y ago
It could also be that there is a potential effect that this study would have been underpowered to detect, and by chance no trend was visible in this population. That's not inconsistent, or even particularly unlikely, if I'm understanding it right.
- A_D_E_P_T 3y ago
  (A) To suggest that the lack of effect in men is a statistical anomaly, and that there IS an effect we're not seeing. (B) To suggest that the effect in women is a statistical anomaly, and that there's nothing there but a fluke. These things, from the data, are approximately equally likely. Because there was zero effect in men -- in fact, men who took the vaccine were apparently more likely to be diagnosed with Alzheimer's, though this trend was extremely slight.
  - adgjlsfhk1 3y ago
    this isn't necessarily true. if the study had 1000 women and 100 men, it would be a lot more likely that the result in men was wrong. similarly, if the effect was 20x weaker in men than women, but still existed you would be much more likely to see no effect in men even though effects existed for both.
    - A_D_E_P_T 3y ago
      Not necessarily true in a theoretical sense, sure. But there's absolutely no indication that they enrolled 10x (or even 2x) more women than men. Nor is there any indication of any effect in men, 20x weaker or otherwise. (If we're charitable, it's pretty much a flat zero.)
    - sbierwagen 3y ago
      Total study size was 282,541 people, 128,322 men and 154,218 women. From supplementary material 1, page 27: https://www.medrxiv.org/content/10.1101/2023.05.23.23290253v1.supplementary-material https://www.medrxiv.org/content/10.1101/2023.05.23.23290253v...
  - shkkmo 3y ago
    > These things, from the data, are approximately equally likely. They aren't. The paper states that 95% confidence interval for men includes a maximum protective effect of up to -1.9 while the 95% confidence for women include a minimum effect of -1.3. Thus it is far more likely that there is a protective effect for man than no protective effect for women.
    - A_D_E_P_T 3y ago
      Are you ignoring the fact that it might have a negative effect, rather than a protective effect? The range for men is -1.9 to +2.1 -- which averages out to +0.2 -- which indeed makes it seem as though the vaccine's trend is to make one slightly more susceptible to Alzheimer's, rather than less susceptible, which is itself borne out in the figure's trend line. (Fig 4.) For women it's -5.3 to -1.3.
      - lamontcg 3y ago
        That means there's a decent chance that the real effect in men is in the range e.g. [-1.9, -1.0] but this study was unlucky or underpowered in men to see that effect.
      - Imnimo 3y ago
        Doesn't this mean that the chance of a true but unobserved -1.9 magnitude effect in men is much greater than the chance of a true but unobserved +0.0 magnitude effect in women?
        A_D_E_P_T 3y ago
        Sure, but, by the same token, it also means that there's a chance of a true but unobserved +2 magnitude effect in men.
      - shkkmo 3y ago
        >Are you ignoring the fact that it might have a negative effect, rather than a protective effect? Nope. We can be 95% confident that there is an effect for women but we can't be 95% certain that there is no effect for men. Given that the error ranges overlap, we don't even have a high level of certainty that the effect for men doesn't equal the effect for women. > The range for men is -1.9 to +2.1 -- which averages out to +0.2 Technically it averages out as +0.1