Ren D, et al. – Authors of this study explored serum antibody response to Moraxella catarrhalis (Mcat) proteins in stringently defined otitis prone children. As per the observations, stringently defined otitis prone (sOP) children was a highly vulnerable population. This population mounted lower serum antibody responses to Mcat candidate vaccine proteins compared to non-otitis prone (NOP) children during asymptomatic nasopharyngeal (NP) carriage and at the onset of acute otitis media (AOM).