The efficacy of pneumococcal polysaccharide vaccine for children suffering from recurrent acute otitis media (AOM) was determined by administration, in a randomized, double-blind fashion, of one of ...two polyvalent vaccines to 124 children aged five to 21 months. The octavalent vaccine contained serotypes commonly associated with AOM: 1, 3, 6A, 7F, 14, 18C, 19F, and 23F. The heptavalent control contained serotypes not commonly associated with AOM: 2, 4, 5, 8, 9N, 12F, and 25F. Recipients of the octavalent vaccine experienced significantly (P < 0.05) less AOM due to serotypes contained in the octavalent vaccine than did children who received the control vaccine. Although the recipients of octavalent vaccine suffered less from AOM due to types in that vaccine than did controls, their clinical experience with AOM was not different. Both groups of children were equally likely to experience at least one episode of AOM after vaccination (70% for octavalent vaccine and 78% for heptavalent vaccine). The mean numbers of episodes of AOM after vaccination also were similar (2.1 for octavalent vaccine and 2.3 for heptavalent vaccine). Similarly, the period of effusion in the middle ear after pneumococcal AOM was identical for both groups. Although immunization with pneumococcal vaccine appeared to reduce the number of episodes of AOM due to serotypes contained in octavalent vaccine, the clinical experience of the children was not favorably affected by this vaccine.
