Passive immunization for the prevention of otitis media

The safety and protective efficacy of exogenously-administered immunoglobulin for the prevention of otitis media has been demonstrated in the clinical trials of the human-derived polyclonal immune globulin used to prevent Haemophilus influenzae type b disease and respiratory syncytial virus infection in high risk neonates and young children. However, this form of therapy is expensive, difficult to administer due to the requirements of slow intravenous infusion or relatively large volumes given intramuscularly, and associated with side effects related to the volume and nature of the immunoglobulin preparation. In contrast, RSV-specific monoclonal antibody has not been as successful as human-derived immunoglobulin in preventing otitis media in high risk infants. The administration of monoclonal-antibody for the prevention of otitis media will be difficult, potentially due to the need for antibody to multiple epitopes of the viral and bacterial pathogens which could be targets. The use of maternal antibody to provide passive immunity to young infants at a time when they are most vulnerable to severe sequelae of infection can also be considered. We have studied maternal immunization using either a 23-valent pneumococcal polysaccharide vaccine or a conjugate H. influenzae type b (Hib) vaccine. Significant levels of maternally-derived Hib or pneumococcal antibody were transferred from the mother to the infant at the time of birth and persisting, for some antigens, through 2 months of age. The use of maternal immunization to prevent otitis media and other respiratory complications remains to be studied, but results of these small clinical trials indicate further clinical investigation is warranted.