Tawfik KO, et al. - Herein, the authors elucidated the trends in the annual prevalence of hospitalization for pediatric acute mastoiditis since the introduction of the 7-valent pneumococcal vaccine in 2000 and the 13-valent vaccine in 2010. No decline was noted in the rates of hospitalization for pediatric acute mastoiditis between 2000 and 2012 despite the introduction of two pneumococcal vaccines. Nonetheless, children 0 to 2 years of age illustrated declining hospitalization rates between 2009 and 2012. This data possibly reflected the protective benefit of the 13-valent pneumococcal vaccine.