LogFAQs > #970750098

The same reason pneumonia kills millions every year while others just feel a bit icky: Medicine, diseases, and the immune system are extremely complicated and there are countless factors that can influence a given infection's prognosis. Genetics, immune function, other conditions, the exact strain you're infected with, the size of your initial pathogen load, vaccination status... There are enough factors that are outside of anyone's control that attributing it to more than blind luck is little more than guesswork. The best you can do is take the steps that are well-known to reduce risk (like getting vaccinated and wearing a mask) and hope for the best.