Why Pandemics Are So Devastating: Immune Evasion and Viral Mutations

The reason why these pandemics have caused such devastating impacts and resulted in the deaths of so many people is because these pathogens (primarily viruses) possess multiple immune evasion mechanisms, complex or elusive antigenic epitopes, and are highly prone to mutations. When human immune systems encounter these viral pathogens, it becomes difficult to generate highly affinity antibodies through normal immune pathways to neutralize the viruses and clear them from the body.