Acute otitis media is the most common reason for the use of antibiotics in the outpatient setting. The annual cost of this disease is estimated to be over $3.5 billion. Historically, antibiotics have been routinely prescribed for patients with otitis media with the intent of decreasing the complications of the infection. Several studies have shown that respiratory viruses frequently cause the infection. Heikkinen and colleagues performed a study to determine rates of middle ear invasion by common respiratory viruses in children with acute otitis media and concurrent virus infections in the upper respiratory tract.

Children between two months of age and seven years of age with a diagnosis of acute otitis media were included in the study. The diagnosis was based on the presence of one or more symptoms: earache, fever, irritability, an inflamed tympanic membrane and the presence of fluid in the middle ear on tympanocentesis. Children who had received antibiotics during the previous week were excluded. Fluid was obtained via tympanocentesis at the time of diagnosis for bacterial culture, viral culture and rapid antigen testing. A nasal wash specimen was also obtained for viral studies. At a follow-up visit two to five days later, tympanocentesis was repeated, and a second nasal wash specimen was obtained. Venous blood for viral antibody testing was drawn at the time of diagnosis and at the third follow-up visit (between days 9 and 12).

A total of 456 children were enrolled in the study, 186 of whom were diagnosed with viral respiratory tract infection. Compared with all the children in the study, those who had a viral illness did not differ in terms of age, race, sex or duration of respiratory symptoms—with the exception of children with influenzavirus infection, who were significantly older. Respiratory syncytial virus (RSV) was isolated from middle ear fluid in 74 percent of children with a viral illness. Other viruses found in these children were parainfluenzavirus, isolated in 52 percent; influenzavirus, isolated in 42 percent; enterovirus, in 11 percent; and adenovirus, in 4 percent.

The most common bacterial organism isolated from middle ear fluid was Streptococcus pneumoniae (25 percent), followed by aemophilus influenzae (23 percent) and Moraxella catarrhalis (15 percent). In 10 percent of the children, two or all three of these pathogens were present at the same time. In 65 percent of ears from which a virus was isolated, a bacterial organism was also found.

The authors conclude that the rates of middle ear invasion vary significantly during acute otitis media. The most common of these invasions is RSV. This finding is consistent with data from several other published studies, which have indicated that RSV is the virus most likely to predispose a child to acute otitis media. The authors state that a vaccine effective against RSV could have a very significant impact on the incidence of acute otitis media.