Over time, there has been a gradual reduction in the disease burden brought on by infectious diseases. Just 30% of the world's overall disease burden was thought to be caused by infectious diseases in 2017. Being one of the underlying causes of the burden of many chronic diseases, obesity is the current public health concern. Over time, there has been a progressive reduction in the burden of infectious disease-related illness. Just 30% of the world's overall disease burden was attributed to infectious diseases in 2017, according to estimates. Yet, this was not always the case; in the 20th century, infectious diseases were blamed for the majority of the world's burden of disability and early deaths. The survival of populations has generally been threatened by the sporadic pandemics of infectious diseases like cholera, smallpox, and influenza. An estimated 50 million individuals perished worldwide during the 1918 influenza epidemic. Osterhaus asserts that viruses may remain dormant and then recur in a population with weakened immunity, resulting in a fresh pandemic wave.
