Thread by @kmpanthagani

People are looking at the percent of vaccinated hospitalizations and getting alarmed. But by itself, this number can't tell you much about how the vaccines are working, as it's highly dependent on the rate of vaccination in a community. Here's some maths to show what I mean👇🏽

As more people are vaccinated (and all else being equal), total hospitalizations will decrease but the *percent* of vaccinated hospitalizations will increase, not because the vaccines aren't working, but because there are more vaccinated people and fewer hospitalizations overall.

To make this point really obvious, look at the scenario where 100% of the population is vaccinated -- there will be way fewer hospitalizations, but 100% of those few hospitalizations will be vaccinated people. So you can't only look at the percentage.

Also, lest anyone get confused, the above data is a hypothetical model of 100,000 people exposed to COVID where the hospitalization rates for the vaccinated and unvaccinated are fixed, and the only variable changing is the % vaccinated.

Some are getting upset that this model isn't taking into account other variables that affect hospitalization rate. It is certainly correct other variables are at play in real world data, but was not the point of this graph. The point was to illustrate that by itself,

% vaccinated hospitalizations is a really bad metric to decide how the vaccines are working, because it is influenced by so many variables, not just the vaccine efficacy (which in this example, is constant).

Of course when it comes to real world data, more variables should be considered. That is the point.

Here is the visualization in Spanish. Thank you to @rusosnith for providing the translation (and the suggestion!)

And here in French. Thank you to @T_Fiolet for providing the French translation and suggestion!

for those wanting a more in-depth explanation, check out this post:

youcanknowthings.com/2021/07/21/som…