[runako]

> case fatality rate is approximately the same

If you vaccinate more people, you would expect that the cases that present at a physician will be selected to be the most severe. If the vaccine reduces most infections to very mild or asymptomatic cases, they will not be counted in the statistics at all.

So it would make sense that introducing a broadly effective vaccine would increase the case fatality rate. (You would also expect fewer severe cases, which is the whole point.)

A functioning vaccine should affect the CFR by changing the denominator of measured cases.

I am reminded of an analogy from improvements in battlefield medicine. As battlefield protocols (on-site treatment, rapid evacuation, etc.) have become more effective, battle fatality rates have fallen. But they have been replaced by a rise in severe chronic injuries like amputations.

[EvgeniyZh]

> If you vaccinate more people, you would expect that the cases that present at a physician will be selected to be the most severe.

Most of cases both before and after vaccinations are not severe. Moreover, the share of severe cases seems to stay the same or even increase ( https://datadashboard.health.gov.il/COVID-19/general , I hope it can be google-translated or something).

As I explained in other reply ( https://news.ycombinator.com/item?id=26142482 ), I expected change in fatality rate due to disproportional vaccination of the group with most of the fatal cases. For 60+ fatality rate is very high, and many of them are vaccinated. For everyone else, the opposite. I agree that if only severe cases were registered, we should've been looking at case number instead (which would be more stable since almost all of those would be registered).

[runako]

> the share of severe cases seems to stay the same or even increase

I can't read the dashboard, but as I indicated this is what you would expect if you have a vaccine that broadly works at controlling the most severe forms of the disease. Vaccinated people whose infections manifest as nothing or a day or two of lethargy are not going to get counted in the statistics.

> I expected change in fatality rate

your expected change in the fatality rate needs to take into account that the real-world denominator has changed and that will not be apparent if you just divide number of fatalities by number of cases. (Because vaccinated people may be more likely to be asymptomatic, and we expect them to not get sick enough to ever present as a case.)

It's important to look at the number of people hospitalized or dying.

[EvgeniyZh]

One again, out of population who are responsible for 90% of deaths (and 10% of cases), more than 80% are vaccinated. Everyone else, like 25%. This got to result in disproportionate change in number of cases and number of deaths.