In that study, involving 34 patients with AOM, 35 with recurrent AOM (rAOM), and 25 with AOM treatment failure (AOMTF), the serum anti-Spn IgG concentration was lowest in the rAOM group during the acute phase, suggesting that the lower immune response in this group could increase the likelihood of AOM recurrence. This evidence concerns the gene SPN and infectious otitis media.