Christian AlthausKonto zweryfikowane

The IFR can also be estimated from seroprevalence studies. A recently published report from Munich (Bavaria) found an IFR of 0.8% (0.6%-1.1%), confirming our earlier estimates. (3/n) http://www.klinikum.uni-muenchen.de/Abteilung-fuer-Infektions-und-Tropenmedizin/de/COVID-19/KoCo19/index.html …

So let's have a look at the Gangelt paper. In general, this is a well done study investigating an early outbreak of #SARSCoV2 in a small community of 12,597 people. They estimate an infection attack rate of 15.5% corresponding to 1,956 people. (4/n)

Then, they estimate the IFR based on 7 deaths (7/1956 = 0.36%). You might say: Wait, what? How can you estimate an IFR based on 7 deaths only? Doesn't chance come into play here? You're right. With such a small number of deaths, you can't get precise estimates of the IFR. (5/n)

I am confused, why does the precision of the estimate depend on the number of deaths and not just the number of observations? If I have a million cases and only observe 7 deaths, i get a pretty tight CI. Am I missing something?