Prevention of otitis media by vaccination.

Otitis media (OM) is one of the commonest infections in childhood and a frequent reason for prescribing antibacterials in infancy. However, the increase in prevalence of antibacterial-resistant respiratory bacterial pathogens has not been matched by the development of new antibacterial agents. Bacterial vaccine strategies aim to prevent OM directly and to reduce nasopharyngeal carriage of pneumococci, thereby reducing the likelihood of developing acute OM. Complete protection against OM would require an approach targeting both bacterial and viral agents. Immunisation with a pneumococcal conjugate vaccine provides protection against acute OM caused by pneumococcal serotypes included in the vaccine, reduces serotype-specific pneumococcal carriage, and reduces carriage of penicillin-resistant pneumococci. However, an increase in non-vaccine serotype OM has been observed in vaccinated children, which may limit the overall effectiveness of this vaccine. New vaccines targeting non-typable Haemophilus influenzae and Mycoplasma catarrhalis are in the early stages of development. Efficacy studies with influenza vaccine have shown the most promising results to date in terms of overall reduction in OM episodes. A more substantial reduction in the burden of OM in childhood would require a combination of vaccines that are effective against the bacterial and viral pathogens involved and that can be administered early in infancy.