A study by Henderson et al in 1982 «Henderson FW, Collier AM, Sanyal MA, Watkins JM, Fairclough DL, Clyde WA Jr, Denny FW. A longitudinal study of respiratory viruses and bacteria in the etiology of acute otitis media with effusion. N E»1 was the first to show a clear relationship between viral upper respiratory infection (URI) and acute otitis media (AOM). This study, which lasted for 14 years, showed that viral infections increased the risk of AOM more that colonization of the nasopharynx by Streptococcus pneumonia or Haemophilus influenzae. The close association of viral infections and AOM was also shown in an extensive study of Ruuskanen et al «Ruuskanen O, Arola M, Putto-Laurila A, Mertsola J, Meurman O, Viljanen MK, Halonen P. Acute otitis media and respiratory virus infections. Pediatr Infect Dis J 1989 Feb;8(2):94-9. »2 (altogether 4 524 episodes of acute otitis within 6 years), in which the monthly incidence figures of AOM were found to follow closely the incidence of viral infections, RS virus in particular. In a study by Arola et al «Arola M, Ruuskanen O, Ziegler T, Mertsola J, Näntö-Salonen K, Putto-Laurila A, Viljanen MK, Halonen P. Clinical role of respiratory virus infection in acute otitis media. Pediatrics 1990 Dec;86(6):848»3 comprising 363 children prone to otitis, 94% were found to have rhinitis or cough at the time of AOM diagnosis. In the fourth study by Chonmaitree et al «Chonmaitree T, Revai K, Grady JJ et al. Viral upper respiratory tract infection and otitis media complication in young children. Clin Infect Dis 2008;46(6):815-23. »4 with 294 healthy children observed for one year, a total of 1295 URI episodes and 440 AOM episodes were found. The overall incidence of AOM that complicated URI was 61%. AOM occurred in approximately half of children with URI due to adenovirus, RS virus, or coronavirus and in approximately one-third of those with URI due to influenza or parainfluenza virus, enterovirus, or rhinovirus.