If half of population responsible for 90% of deaths is vaccinated it should affect death-per-case ratio.
Edit: Also, when you look at the JHU data (e.g. via google), it shows a peak at Jan 15th in the number of cases followed by a steady decline. The number of deaths peaks on Jan 28th, followed by a similar, steady decline. Which is as expected, so I would say we are already seeing the effects on the number of deaths.
Sorry that I didn't look at the data earlier before replying.
My hypothesis (it's not mine but I agree with it): if population with high death risks is disproportionately vaccinated, at the level it can make visible effect on case count for this population, it should have effect on case fatality rate. Of course, multiple factors can reduce/slow down the decline, but it should be there. Reducing death probability by half for the 60+ people without changing anything else should significantly reduce case fatality rate.
Yet the data does not support it: https://ourworldindata.org/coronavirus-data-explorer?zoomToS...
The case fatality rate peaked at the end of November, slightly declined until mid-January, then grown a bit and is almost constant in last three weeks.
So, the options I see are: either no effect at all can be seen yet behind the noise (it's hard to believe for me), or there is some factor compensating for the case fatality rate reduction (I can think of what could increase fatality that much and exactly compensate the effect), or the hypothesis is wrong (I can't see why either)
So I would argue that we do see the CFR being lower than the peak we would expect without working vaccinations.
The vaccination also does no good if you are already infected, and with the spike in infections in Israel coinciding with vaccination ramp up, those will be tricky to separate out.
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.
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).
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.
This reduces the number of cases.
A good explanation is that the vaccine is not working. ( people are in denial) I looked at the Pfizer numbers and my conclusion is the it's doing nothing.