Infectious diseases make up three of the ten slots in the World Health Organization's top 10 causes of death and account for millions of deaths annually across the globe. Despite these high numbers, however, diseases like COVID-19 and tuberculosis don't kill the majority of people they affect: COVID-19 kills an estimated 1% of those infected, based on totals reported by the World Health Organization (WHO), and tuberculosis kills fewer than 15%, according to WHO reports.
But do any infectious diseases have a 100% fatality rate? And if so, what makes them so deadly?
