I recently noticed that the Pfizer immunobridging trials, presumably set up to demonstrate that their COVID-19 vaccines elicit the same antibody response in children as was seen in 16-25 year olds, for whom efficacy has previously been demonstrated, have a strange criteria for “success”. GMT: geometric mean titer. This is a measure of the antibody titers. We use the geometric mean because this data is quite skewed (it is also why you typically see it plotted on the log scale). For those o...
