You have already fought off more infections than you could name. Most of them never got far enough to become a story — a sore throat that did not develop, a cell that went wrong on a Tuesday and was dealt with by Wednesday.
It is an odd sort of ability, because there is no way to practise it and no way to watch it work. The only evidence is negative: everything that did not happen.
Which makes the track record invisible and enormous at the same time. Whatever is being asked of that system now, it is not being asked of a beginner.