Selection flowchart for study of invasive Streptococcus pneumoniae disease (IPD) cases in South Africa, 2003–2013. Cases were reported by Group for Enteric Respiratory and Meningeal Disease Surveillance sites (GERMS-SA). Years indicate prevaccine (2003–2008), baseline (2005–2007), and postvaccine (2013) periods. Nonenhanced sites only submitted isolates and accompanying laboratory report forms, which included patient age and sex and the date and source of the specimen; enhanced sites (primarily tertiary hospitals) implemented enhanced surveillance, in which dedicated surveillance officers collected additional clinical information on identified patients.