DHRS2 and infectious otitis media: Widespread implementation of pneumococcal conjugate vaccines (PCVs)—namely the 7-valent PCV (PCV7), 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV), and 13-valent PCV (PCV13)—in infant national immunization programs has reduced pneumococcal diseases in children, including invasive pneumococcal disease (IPD), acute otitis media (AOM), and community-acquired pneumonia (CAP).