Background: The novel pneumococcal conjugate vaccine, PncCRM, has been shown to prevent acute otitis media caused by vaccine serotypes and to reduce otitis surgery. Our aim was to assess long term efficacy of the vaccine on tympanostomy tube placements.
Methods: Children with complete follow-up in the Finnish Otitis Media Vaccine Trial up to 24 months of age and still living in the study area (1490 of 1662 randomized at 2 months of age) were invited to a single visit at 4-5 years of age. The children had been vaccinated at 2, 4, 6 and 12 months of age with PncCRM or hepatitis B vaccine (control). Tympanostomy tube placements reported by parents at the visit were verified from hospital and private medical center records. Additionally, tympanostomy tube placements of all children were verified from the hospital discharge registry. Vaccine efficacy (VE) was estimated by comparing all events of tympanostomy tube placement between vaccine groups.
Results: During the vaccine trial (2-24 months of age), VE (95% confidence interval) in preventing tympanostomy tube placement was only 4% (-19-23%). Altogether 756 children were enrolled for the follow-up study. After 24 months of age, the rate of surgery was 3.5 per 100 person-years in the PncCRM and 5.7 per 100 person-years in the control children, giving VE of 39% (4-61%). In the hospital-based data of all children (N = 1490), VE of 44% was obtained (19-62%).
Conclusions: Receipt of PncCRM vaccine at infancy was associated with a reduction in tympanostomy tube placement from 2 to 4-5 years of age.