Otitis media (OM) - inflammation of the middle ear - is a common childhood affliction the world over. Every year, there are about 1.5 million cases in the UK, and 2.2 million cases in the US.
* It should only be in cases of prolonged hearing loss, affecting speech development. Some studies advocate a three-month waiting period, though one suggests that a delay of even six months
* Monitor the ears for signs of acute infection. As well as effusion, the sufferer will have fever, pain, irritability and poor appetite, among others. The ear will be very red and hot, with a bulging eardrum;