COVID-19 affects every individual differently. Even if they weigh the same and suffer from the same health conditions, they may develop different symptoms and face diverse difficulties. It is one of the mysteries scientists are still trying to figure out. Based on the several pieces of research carried out till now, genes, sex, environment, diet and several other factors may increase the chances of severe infection and even develop long COVID. In yet another attempt to understand the nature of the infectious virus, scientists recently conducted an elaborate study in which it was revealed that a person’s fingernails can tell if he/she is more prone to suffer from long COVID-19.