The frequent ear infections suffered by some infants during the first two years of life can be difficult to treat. Most are caused by
Juhani Eskola and colleagues investigated 1662 infants in a randomised, double-blind trial of the heptavalent pneumococcal polysaccharide conjugate vaccine CRM197. The children received either the pneumococcal vaccine or a hepatitis B vaccine as a control at 2, 4, 6 and 12 months of age; they were followed up until the age of two years.
The vaccine reduced by 57% the number of episodes of acute otitis media caused by the serotypes included in it. The number of otitis episodes attributed to serotypes that are cross-reactive with those in the vaccine was reduced by 51%. But the number of episodes due to all other serotypes increased by 33%.