The status of RSV vaccines: an update

Respiratory syncytial virus (RSV) is one of the most important causes of viral lower respiratory tract illness in infants and children globally. It often causes severe and even fatal infections, particularly in children aged under 6 months, and RSV is considered responsible for onethird of deaths resulting from acute lower respiratory infection (ALRI) in the first year of life. There is no vaccine currently available to protect from RSV infection, especially the severely affected risk groups. Immunoprophylaxis with the neutralizing monoclonal antibody, palivizumab, is used to prevent RSV disease in very premature infants and high risk individuals. Live-attenuated vaccine approaches have been in development for the past decades, but to achieve immunogenicity, their safety was compromised in the past. In recent years, several RSV vaccine candidates using various technologies and targeting different populations and age-groups have emerged. In the present review, the current status of RSV vaccine development is presented. Sixty RSV vaccine candidates are in development, targeting the whole range of age-groups, of which 16 vaccine candidates are currently in clinical development, while most are at a preclinical stage.