By some estimations, more than 75% of children will have had otitis media at least once by the time they start school, with cases being especially common in infants. That’s why a study in Clinical Infectious Diseases is so important: It analyzes the effect of a 13-valent pneumococcal conjugate vaccine (PCV13) on the occurrence of first and subsequent otitis media (OM) episodes in early childhood.

Vanderbilt University Medical Center researchers compared the risk of OM episodes among children in Tennessee aged 2 years and younger before and after PCV13 introduction. PCV7 was added to the recommended U.S. childhood vaccination schedule in 2000, with PCV13 replacing it in 2010.

Looking at the years 2006 to 2014, researchers identified consecutive annual (July-June) cohorts of Medicaid-enrolled children from birth through age 2 years. They pinpointed OM episodes using coded diagnoses and classifying diagnoses less than 21 days apart as the same episode.

Compared in the study were adjusted hazard ratios (aHRs) for OM for PCV7 (2006-2010)- versus PCV13 (2011-2014)-era birth cohorts. Secondary analyses examined pressure-equalization tube (PET) insertions and compared the risk of recurrent OM (i.e., three or more episodes in 6 months or four or more in 12 months) between PCV7- and PCV13-era birth cohorts.

Overall, 618,968 OM episodes and 24,875 PET insertions occurred in the 368,063 children in the study.

Results indicate that OM and PET insertion rates increased during the PCV7 years and declined after PCV13 introduction. Researchers point out that both OM and PET insertion risks were lower in the 2013-2014 cohort compared with the 2009-2010 cohort (aHR: 0.92 [95% CI, 0.91-0.93] and aHR: 0.76 [95% CI, 0.72-0.80], respectively). That led them to conclude that PCV13 introduction was associated with declines in the risk of first, subsequent, and recurrent OM.

“The transition from PCV7 to PCV13 was associated with a decline of OM among children <2 years due to a reduction in the risk of both the first and subsequent OM episodes,” the study authors write.

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