Over 90 strains of S. pneumoniae have been identified with 10 strains found to be the cause of approximately 62 percent of all cases of invasive pneumococcal disease globally. In the U.S., 80 percent of invasive pneumococcal disease found in children six years of age and under were caused by seven common pneumococcal strains. In 2020, there were 11,718 confirmed cases of invasive pneumococcal disease in the U.S, with 536 of those cases occurring in children under five.
