Acute otitis media in the era of effective pneumococcal conjugate vaccine:will new pathogens emerge?

The immunogenicity of pneumococcal conjugate vaccine (PCV) in young infants and its serotype-specific efficacy in otitis media (OM) results in a modes t reduction in total episodes of OM and a more substantial reduction in dis ease due to the most frequent pneumococcal serotypes. Since PCV will only p revent disease due to the most common serotypes, concerns about potential c hanges in the microbiology of OM have emerged. insight into potential chang es can be obtained from reviewing middle ear and nasopharyngeal isolates fr om studies of antimicrobial prophylaxis and bacterial polysaccharide immune globulin for prevention of OM and PCV for prevention of invasive pneumococ cal disease, respectively. In children receiving PCV, a shift in serotypes of SP colonizing the nasopharynx has been observed. Since non-vaccine serot ypes are already present in the community as the etiology of acute purulent OM, it is predictable that these non-vaccine serotypes will become more co mmon especially in children less than two years of age. (C) 2000 Elsevier S cience Ltd. All rights reserved.