The effect of pneumococcal conjugated vaccines on occurrence of recurrent acute otitis media among infants diagnosed with acute otitis media at an age younger than 2 months.

To examine the impact of pneumococcal conjugate vaccines (PCV) on the occurrence of recurrent acute otitis media (rAOM) among infants diagnosed with an early acute otitis media (AOM) episode. Retrospective cohort study of pediatric patients with a first episode of AOM at an age < 2 months. Data included clinical, demographic, and microbiological findings at the first AOM episode. In addition, a 5-year follow-up after the patient's first episode was completed from the medical records. This information included documentation of rAOM episodes and complications of AOM (hearing loss, speech disturbance, mastoiditis, and tympanic membrane perforation) and of ear-related surgical procedures (ventilation tube placement, adenoidectomies, and mastoid surgery). Two groups were studied: patients diagnosed between 2005 and 2009 (representing the unvaccinated group, group 1) and those diagnosed in 2010-2014 (the vaccinated group, group 2). A total of 170 infants were diagnosed with a first AOM episode at an age < 2 months; 81 of them belonged to group 1 and 89 to group 2. Streptococcus pneumoniae was isolated in the middle-ear fluid in the first AOM episode in 48.1% of the patients in group 1 and in 30.3% in group 2 (P = 0.0316). 49/81 (60.5%) infants in group 1 were diagnosed with rAOM versus 39/80 (43.8%) in group 2 (P = 0.0298). No statistical differences were found between the groups with respect to long-term complications or need for surgery later in life.   Conclusion: Our study showed a significant decrease in the occurrence of rAOM in infants diagnosed with AOM during the first 2 months of life and timely immunized with PCVs following this initial AOM episode. What is Known: • 30% of children experience recurrent AOM (rAOM) at the first year of life. The earlier the age of the first AOM, the greater the risk for future complications. • After the introduction of PCVs, the overall pneumococcal AOM incidence declined. We investigated the future effect of PCVs on rAOM occurrence, when administered after the first AOM episode. What is New: • A retrospective cohort of 170 infants with a first AOM episode at an age <2 months and followed for 5 years, showed a significant decrease (28.0%) of rAOM in immunized infants following the initial AOM episode. • Our findings supplement previous data suggesting that the widespread PCVs use prevents rAOM by preventing early AOM and emphasize the importance of timely administration of the PCVs.