Foreword: Prevention of COVID-19, Influenza, and Respiratory Syncytial Virus in At-Risk Populations

further compounded by the fact that over half (51%) of the global adult population 60 years of age has multimorbid conditions [6].For the first time, we have safe and effective vaccines for SARS-CoV-2, influenza, and RSV, marking a historic milestone in vaccine development.Despite the availability of vaccines and evidence-based recommendations supporting annual vaccination, achieving optimal vaccination coverage remains a continuous challenge.This five-part journal supplement provides an in-depth review covering the disease burden of these respiratory viruses, risk factors for severe outcomes, complications and long-term sequelae of infection, and the multidimensional impacts of vaccination.In addition, the supplement reviews current barriers and strategies toward achieving optimal vaccination coverage among at-risk adult populations; these insights may inform public health strategies and immunization policies and guidelines toward standardized, evidence-based vaccine clinical practices.The supplement begins with an article by Hanage and Schaffner, which describes the epidemiological and clinical characteristics of SARS-CoV-2, influenza, and RSV infection in older adults.The authors characterize the overall disease burden of these respiratory viruses, including the clinical presentation, transmission patterns, and seasonality.The long-term health and economic consequences associated with infection and disease are discussed, as well as