Vaccination against respiratory syncytial virus in pregnancy: a suitable tool to combat global infant morbidity and mortality?

Respiratory syncytial virus (RSV) is the most important viral cause of pneumonia in early childhood (ie, younger than 2 years), responsible for high infant morbidity and mortality worldwide. It is widely accepted that an effective vaccine against RSV would have a major impact on child health globally. Despite the setbacks of the clinical trials in the 1960s, there has been a recent and significant revival of interest in vaccines against RSV, with several promising candidates undergoing evaluation. In this Review, we describe the epidemiological and immunological background to RSV infection and subsequently focus on the promising pipeline of RSV vaccine development. We discuss the potential for implementation of a safe and immunogenic RSV vaccine within the context of global health and with regards to a range of strategies, including vaccination of women during pregnancy, which is likely to emerge as a beneficial and feasible public health tool. This approach would provide interim protection to vulnerable, RSV-naive infants and other high risk groups, in which the burden of admission to hospital and death is greatest. Extending research and implementation from resource-rich to resource-poor settings is required to enhance our understanding of RSV immunity and inform vaccine development and delivery strategies for all settings. We summarise key outstanding issues for researchers and policy makers to understand the interplay of biological and non-biological factors affecting design and distribution of a successful RSV vaccine globally.