All Cause Mortality: what it is and why it's the best way to evaluate treatments for deadly diseases

If we want to evaluate the efficacy of a new treatment such as a drug or vaccine against a particular deadly disease then it is not enough to focus purely on how effective the treatment is at stopping the disease. We also have to consider the trade off between effectiveness and safety - do the risks outweigh the benefits. The simplest and most objective way to do this is to determine whether fewer people who get the treatment die compared to those who don’t get the treatment. In other words we have to compare the all cause mortality of the treated versus the untreated.