Impact of the pneumococcal conjugate vaccine on otitis media

Context. The heptavalent pneumococcal conjugate vaccine (PCV) is recommended for infants to protect against invasive disease, but its impact on otitis might also have public health importance. Objective. To examine the impact of PCV on the incidence of otitis media, frequent otitis media and tympanostomy tube procedures and to assess whether the effectiveness of the vaccine wanes after age 24 months and varies by race, sex or season. Design, setting and patients. From 1995 to 1998, 37 868 children at Kaiser Permanente in Northern California were randomized to receive PCV or a control vaccine in a double blind trial and were followed through April 1999. Interventions. Children received a primary series at 2,4 and 6 months of age and a booster at 12 to 15 months. Main outcome measures. Visits for otitis, frequent visits for otitis and tympanostomy tube procedures. Otitis was ascertained from diagnosis checklists routinely marked by physicians. Results. Control children averaged 1.8 otitis visits per year. Children given PCV had fewer otitis visits than control children in every age group, sex, race and season examined. Intention-to-treat analysis permitted rejection of the null hypothesis that PCV is ineffective against otitis media (P < 0.0001). In children who completed the primary series per protocol, PCV reduced otitis visits by 7.8% [95% confidence interval (CI), 5.4 to 10.2%] and antibiotic prescriptions by 5.7% (CI 4.2 to 7.2%). Frequent otitis was reduced by amounts that increased with otitis frequency, from a 10% reduction in the risk of 3 visits to a 26% reduction in the risk of 10 visits within a 6-month period. Tube placements were reduced by 24% (CI 12 to 35%). Conclusion. In children followed up to 3.5 years, PCV provided a moderate amount of protection against ear infections while reducing frequent otitis media and tube procedures by greater amounts.