The purpose of this study is to establish retrospectively the incidence rates of invasive pneumococcal disease in children aged less than 5 years. The investigators allocate the El Hasa region for the study because it has higher incidence of sickle cell anemia. The study will include data from 2003 to 2007(before introduction of the vaccine) and then for 2008 and 2009 (after introduction of the vaccine).

Data will be collected from patents files or records for 5 years before the introduction of the vaccine and for 2 years after the introduction of the vaccine. We assigned 4 doctors in each hospital to carry and supervise the work.

Inclusion Criteria:

• Invasive pneumococcal disease
• Children under 5 years
• Children lived in Elhasa region

Exclusion Criteria:

• Children above 5 years
• No invasive pneumococcal disease

children under 5 years with invasive pneumococccal dis.