A retrospective epidemiological study of invasive pneumococcal infections in children aged 0-5 years in Bahrain from 1 January 1999 to 31 December 2003.

Pneumococcal diseases caused by the bacterium Streptococcus pneumoniae are a worldwide public health problem. The objective of this study was to determine the incidence of pneumococcal diseases in children aged <5 years in Bahrain. A total of 371 cases of pneumococcal infections in children aged <5 years, recorded in 5 hospitals in Bahrain from 1 January 1999 to 31 December 2003, were retrospectively reviewed. Case definition required microbiological confirmation (i.e., isolation of S. pneumoniae from blood, cerebrospinal fluid, or any other normally sterile biological fluid) or clinical diagnosis if microbiology test results were inconclusive. During the study period, the average annual incidence of invasive pneumococcal disease (IPD) in children aged <5 years was 115 per 100,000, ranging from 42 per 100,000 in 1999 to 208 per 100,000 in 2003. The annual incidence of IPD in children aged <1 year was 471 cases per 100,000. The reported annual incidence of microbiologically confirmed IPD (meningitis, septicemia, and bacteremia) increased from 3.91 per 100,000 in 1999 to 109.77 per 100,000 in 2003. The greatest disease burden was in children <2 years old: this age group included 75% of meningitis cases, 89.2% of septicemia/bacteremia cases and 81.5% of pneumococcal pneumonia cases. In conclusion, the estimated annual incidence of IPD in children aged <5 years in Bahrain was unusually high. Factors responsible may include the wide and uncontrolled use of antibiotics, the mobility of a large proportion of the population, and possible susceptibility to risk factors such as sickle cell anemia and respiratory illnesses.