Respiratory Virus Vaccines

This chapter reviews the main viral pathogens of the respiratory tract, the immune responses they induce, currently available vaccines, and vaccines that are in development to control them. The main viruses responsible for acute respiratory infection in people include respiratory syncytial, influenza, human parainfluenza, human metapneumo-, human rhino-, corona-, and adenoviruses. Licensed vaccines are available only for influenza virus, with vaccines against the other pathogens either in clinical trials or in preclinical stages of development. The majority of studies evaluating respiratory virus vaccines measure serum antibody responses, because, although both cellular and humoral responses contribute to the clearance of a primary infection, neutralizing antibodies are known to protect against secondary infection. Humoral responses can be readily detected after vaccination with inactivated or subunit vaccines; however, fewer individuals seroconvert after vaccination with live vaccines. Alternative immune mechanisms such as mucosal antibody responses are probably responsible for protection by live attenuated vaccines, and immune correlates of protection are under investigation.