Long-term Effect of Pneumococcal Conjugate Vaccines on Tympanostomy Tube Placements

Background: We have previously shown that the 7-valent pneumococcal conjugate vaccine (PncCRM) given in infancy is effective in reducing tympanostomy tube placements up to 4 to 5 years of age. This study aimed to assess the effectiveness of pneumococcal conjugate vaccines PncCRM and PncOMPC from 2 up to 13 years of age. Methods: Altogether 2497 children participated in the Finnish Otitis Media Vaccine trial conducted in 1995 to 1999 and were vaccinated at 2, 4, 6 and 12 months of age with PncCRM or PncOMPC or hepatitis B vaccine as controls. The data for tympanostomy tube placements were collected from health registers including hospital and private office operations. Vaccine efficacy was estimated by comparing incidences of tympanostomies from 2 to 12-13 years of age in each of the pneumococcal vaccine groups with the control group. Results: Register data were searched for 2474 subjects. A total of 535 tympanostomy tube placements were identified in the health registers from 1998 through 2008 with a cumulative incidence of 14.6% from 2 to 13 years of age in the control group. The vaccine impact was age-dependent: from 2 through 5 years of age the vaccine effectiveness was 34% (95% confidence interval: 1% to 52%) for PncCRM and 6% (-28 to 31) for the PncOMPC vaccine. For the age group of 6 to 12-13 years the vaccine effectiveness estimates for the PncCRM and PncOMPC groups were -13% (-137 to 46) and -2% (-123 to 54), respectively. Conclusions: PncCRM vaccine reduced the tympanostomy tube placements up to 5 years of age. No impact on new surgical procedures could be demonstrated after that but the benefit achieved was sustained.