Efficacy of pneumococcal vaccination against recurrent otitis media. Preliminary results of a field trial in Finland.

For this study, 781 children, and 3 to 83 months, after presenting with acute otitis media, were immunized with either 14-valent pneumococcal or Haemophilus influenzae type b capsular polysaccharide vaccine. The vaccines were tolerated well. Antibody responses to the 14 pneumococcal polysaccharide types, measured by radioimmunoassay, were fair to good and increased with age, with the exception of types 1, 6 and 12 to which the responses were generally poor. During the follow-up of 1-17 months, average 13 months, 45 vaccine type (except type 6) pneumococcal recurrences were met among 456 pneumococcal-vaccinated and 45 among 288 H. influenzae-vaccinated children, at least six months old (P < .05). The corresponding protective efficacy by the pneumococcal vaccine was 37%, for the first six months, 51% (P < .01). No protection by the pneumococcal vaccine was seen against group 6 pneumococci, nor among 19 infants under six months of age. Nonvaccine type pneumococcal ad H. influenzae recurrences did not significantly concentrate in either of the vaccination groups. Thus, it seems that parenteral immunization of children can reduce the recurrence rate of otitis media caused by pneumococci of types (except type 6) present in the vaccine.