Acute otitis media (AOM) is an important reason for medical visits and antibiotic use in children, with possible complications. Pneumococcal conjugate vaccines (PCV) have been developed from 2000, with first the apparition of the 7-valent PCV (PCV7), and from 2013, of the 13-valent PCV (PCV13). First developed to prevent invasive pneumococcal infections, they have been shown to reduce the number of AOM as well. PC13 has allowed to reduce the nasopharyngeal carriage of the majority of pneumococcal serotypes found in AOM, with a reduction of 77% of pneumococcal AOM, according to one study.