Etiology Human metapneumovirus (HMPV) is a respiratory virus that has emerged as one of the most common causes of serious lower respiratory tract illness in children throughout the world. Etiology HMPV is an enveloped, single-stranded, nonsegmented, negative-sense RNA genome of…
Respiratory syncytial virus (RSV) is the major cause of bronchiolitis (see Chapter 418 ) and viral pneumonia in children younger than 1 yr of age and is the most important respiratory tract pathogen of early childhood. Etiology RSV is an enveloped…
Overview of Innate and Adaptive Antiviral Immunity Viral host defense mechanisms of humans depend on a combination of tightly integrated innate and adaptive immune mechanisms. Key innate immune mechanisms include antiviral and proinflammatory cytokines, such as type I interferon (IFN),…
Overall Principles Vaccination has been the most effective medical intervention in the modern era. Historically, the focus on vaccine development and implementation programs has been on preventing infectious diseases during infancy and early childhood. The current vaccine schedule for early…