Otitis media (inflammation of the middle ear) is usually caused by infection from bacteria such as Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. It affects people of all ages, but is commonly diagnosed in early childhood with a peak incidence between six and 15 months of age. Ear pain (otalgia) is the hallmark of acute otitis media (AOM) and affected children either complain of or manifest behaviour that parents interpret as indicating ear pain. Otitis media with effusion (OME; also known as 'glue ear') may cause hearing loss with associated developmental delay. Around 164 million people worldwide have long-term hearing loss caused by this condition.