The journey to a respiratory syncytial virus vaccine.

Objective: The high burden associated with respiratory syncytial virus (RSV) has made the development of RSV vaccine(s) a global health high priority. This review summarizes the journey to an RSV vaccine, the different strategies and challenges associated with the development of preventive strategies for RSV, and the diverse products that are undergoing clinical testing.

Data Sources: Studies on RSV biology, immunology, epidemiology, and monoclonal antibodies (mAbs) and vaccines were searched using MEDLINE. We also searched PATH.org and ClinicalTrials.gov for updated information regarding the status of RSV vaccines and mAbs undergoing clinical trials.

Study Selections: We selected relevant studies conducted in infants and young children, pregnant women, and elderly population for the prevention of RSV infection.

Results: Identification of a safe and immunogenic vaccine has been an important but elusive initiative for more than 60 years for different reasons, including the legacy of formalin-inactivated vaccine, our limited understanding of the immune response to RSV and how it relates to clinical disease severity, or the need for different end points according to the different vaccine platforms. Nevertheless, there are currently 39 vaccines and mAbs under development and 19 undergoing clinical trials.

Conclusion: Over the past decade, there have been significant advances in our knowledge of RSV molecular and structural biology and in understanding the human immune response to RSV. Despite the barriers, there are several promising mAbs and RSV vaccines undergoing clinical trials that hope to offer protection to the most vulnerable populations.