Background COVID-19 is a pandemic, resulting in large number of deaths all over the world. Methods The risk factors for mortality are not clearly understood. We are presenting a new hypothesis. Results Virus become more virulent as it passes through weaker hosts and vice versa. Conclusions Viruses become more virulent when it passes through weaker and older hosts. It will be worth analysing the transmission chain of COVID-19 from this perspective.

Background COVID-19 is a pandemic, resulting in large number of deaths all over the world. Methods The risk factors for mortality are not clearly understood. We are presenting a new hypothesis. Results Virus become more virulent as it passes through weaker hosts and vice versa. Conclusio...