Your post is likely to be severely misinterpreted. I've already seen people sharing it with the takeaway comment that, "The real world data has shown that the death rate among the vaccinated, if infected with COVID, can be 3 to 5.7 times higher than the death rate of the unvaccinated."

A majority of people will read that as saying that the vaccine makes you 3 to 5.7 times more likely to die of COVID. Some of those who read more carefully will notice the "if infected" and interpret it to mean that if you catch COVID-19 after being vaccinated you are 3 to 5.7 times more likely to die than if you had caught COVID-19 without being vaccinated. As you point out in the "More graphs" section, and as discussed in the comment by Sandra and your response, THAT'S NOT WHAT IT MEANS.

The 5.7 is a completely meaningless number found by dividing the fatality rate in a group roughly half of whose members are over 50, by the fatality rate in a group only 2% of whose members are over 50. It is dividing apples by oranges. It says nothing about how getting vaccinated affects the chances of an individual dying if they get COVID-19. If the only confounding variable were whether someone were over 50, then the data in that table would imply that if you are over 50 and you get a breakthrough infection you have a 1 - (220/13,427)/(131/2,337) = 71% LOWER chance of dying than if you had gotten infected without being vaccinated, and if you are under 50 it is 1 - (4/15,346)/(34/119,063) = 9% lower, with wide confidence intervals on both. (This is a nice example of Simpson's paradox -- the trend in each group is different from the apparent overall trend.) There are many other confounding characteristics, such as finer breakdown of age, comorbidities, immune strength, etc, that are likely to correlate both with the chance of a breakthrough infection and with the chance of dying if infected, so after correcting for them it is likely that vaccination decreases the chance of death if infected even more. Of course you are correct that there's no reason to believe the decrease is as much as 95%, and certainly the data that is being presented doesn't show it, but none-the-less, it is very likely that there is some benefit, and probably a substantial one for the most vulnerable people.

You've done an excellent job of explaining why claims of vaccine benefit for those with breakthrough infections has been overstated, but most people will not read it all, and will instead come away with a faulty understanding in the opposite direction. Rather than interpreting it to mean that people need to be careful even after being vaccinated, it will be interpreted by many people to mean that they should not get vaccinated at all. I'm sure that is not your intent.

Could you edit your post to replace the assertion about 3 to 5.7 higher death rate with something that is less likely to be misinterpreted?

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What to make of the information coming out of Florida? “The virus has a new target: the unvaccinated and younger people,” says Mary C. Mayhew, President and CEO, Florida Hospital Association in a recent release. “Previously healthy people from their teens to their 40s are now finding themselves in the hospital and on a ventilator. Regardless of your age, get vaccinated, if eligible! What you heard last year and last spring about this virus mostly targeting seniors and those with pre-existing conditions is not true today.”

The media is echoing this. But the data in this article suggests the opposite — if I’m understanding correctly?

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Looking at the definition of "vaccinated" in the Israel chart, it only includes people post 14 days after their second round. It isn't stated explicitly, but it appears that "unvaccinated" includes everyone else: those never vaccinated, vaccinated with one dose, or vaccinated with two doses but within 14 days of the second.

Isn't this a much bigger problem? How can we know what the relative risks are for vaccination without knowing the risks during the "actually vaccinated but still counted as unvaccinated" phase? Shouldn't the data have at least 3 categories? Ideally, each category would have separate counts.

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Not likely that infection was verified by lab culture or some other means than a single PCR positive. Also, govt guidance on testing changed for the vaccinated. That is, unless showing symptoms, the vaccinated were excluded from PCR testing. Did this apply to the trials as well? Also guidance changed when testing the vaccinated so that the Cycle Threshold was reduced markedly from the rather high Cycle Threshold used routinely prior to the trials. Also, these vax trials at some point eliminated the control group by vaccinating. What is of concern is that the data gathering process has been severely botched and this may produce significant error or weak conclusions that can not actually guide policy-making much less the decision-making of individuals based on their circumstances. Hence the broad push for all to get vaccinated in a hurry. However, the rollout to the general population has overlapped the trials which are ongoing. Very messy all around.

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Thank you for your effort. I hope I understood your article correctly. However, I am still puzzled by this:

">90% less likely to get infected — true"

... so there is a benefit for getting a vaccine after all? Just in the event If I get infected after I am fully vaccinated the chances are such as described in article? Please correct me if I am wrong.

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Are there any updates on this topic? I have come across these calculations: https://www.covid-datascience.com/post/israeli-data-how-can-efficacy-vs-severe-disease-be-strong-when-60-of-hospitalized-are-vaccinated

Why do these differ so much?

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Before setting up the trials, what was the substantive baseline risk of infection? Stratified by age or other criteria? The infection fatality rate appeared very low before the trials began.

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Do I understand correctly? The initial trials done by the pharma companies showed a reduction in disease but it was a complete mystery why. They did not measure the rate of infection. Combined with the fact that some vaccinated people still got infected, many suspected that it just lessened symptoms but not infection (like IPV polio vaccine). But the results of this study suggest that the trial results are indeed explained by reduction in infection and it has almost no effect on symptoms.

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Looking at the first reference, I fail to see how "the death rate among the vaccinated, if infected with COVID, can be 3 to 5.7 times higher1 than the death rate of the unvaccinated". For example, Table 5 - for <50 group, the death rates are near identical. For >=50 they are 1.638% (220/134.27) for double-vaccinated vs 5.61% (131/23.37) for unvaccinated.


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