Pneumococcal conjugate vaccination and otitis media: differences among high-risk and low-risk populations.

The impact of the heptavalent pneumococcal conjugate vaccine (PCV7) on the natural history of otitis media (OM) has been studied recently. In a high-risk population, PCV7 significantly reduced the risk of recurrent, bilateral or multiple tympanic membrane perforation, as well as the risk of chronic suppurative OM at 9 months of age. PCV7 did not reduce the time to the development of OM nor the burden of OM. Major challenges are the polymicrobial etiology of OM (Streptococcus pneumoniae and Haemophilus influenzae) in high-risk populations and the serotype replacement among pneumococcal strains. A vaccine including nontypable H. influenzae and 11 pneumococcal serotypes has been identified as a more efficacious option for preventing OM. In the near future, the development and evaluation of a vaccine containing pneumococcal protein, such as pneumococcal surface protein A, which is a structurally variable and serologically cross-reactive surface protein important to the pneumococcal virulence, will be a potential tool against OM.