<s>[INST] What is an ear infection? [/INST] An ear infection is when the middle ear has a buildup of fluid in it. This can be caused by improper draining or inflamed sinuses. Ear infections are most common in children because the tubes that drain fluid are horizontal for children. As we age, they start to become vertical and allow draining to happen more easily. Source: ENT SURGEONS US. Link: https://www.entsurgeons.us/my-blog/885678-faqs-about-ear-infections/. Field: Otolaryngology. Disease: Ear Infection </s>