 Among children under two years of age, the overall incidence of IPD declined nearly 70% after PCV introduction, and rates of IPD caused by bacteria specifically targeted by the vaccine decreased nearly 90%.Due to the indirect protection conferred by herd immunity, a significant decline in IPD in children and in unvaccinated adults has also been shown.Pneumovax 23 is used for all ages and, according to the enclosed patient information leaflet, has a reported 76% to 92% protective efficacy (pneumococcal types 1, 2, 3, 4, 5, 6B**, 7F, 8, 9N, 9V**, 10A, 11A, 12F, 14**, 15B, 17F, 18C, 19A**, 19F**, 20, 22F, 23F** and 33F** are included, where ** indicates drug-resistant pneumococcal infections; these are the 23 most prevalent or invasive pneumococcal types of "Streptococcus pneumoniae").