Abstract
A series of episodes of acute otitis media was studied with reference to bacterial findings and specific serological responses in 48 children with histories of frequent episodes before. D. pneumoniae and H. influenzae were the most frequently isolated pathogens. Re-isolations after therapy were often made in episodes with slow healing or therapeutic failure. Most children harboured pathogens in nasopharynx even when they had no signs of respiratory tract infections. Homologous relapses were seen only in few cases and never with pneumococcus type 3 and only once with H. influenzae type b. Specific serological responses were demonstrable generally in children over 2 years of age. D. pneumococcus type 3 and H. influenzae type b generally provoked antibody response. No levels indicating immunoglobulin deficiencies could be found in the children.