Report on invasive disease and meningitis due to Haemophilus influenzae and Streptococcus pneumonia from the Network for Surveillance of Pneumococcal Disease in the East African Region

Abstract

Pneumococcal disease in young children has not been as well characterized in East Africa as it has been in industrialized countries. Although pneumococci are likely to cause substantial mortality and morbidity, universal diagnostic challenges plus the rudimentary nature of public health surveillance make the true epidemiological characteristics of these diseases difficult to ascertain with these methods alone. However, local data are critical to inform the debate on vaccine deployment and assess vaccine impact. The Network for Surveillance of Pneumococcal Disease in the East African Region has worked to expand the World Health Organization Paediatric Bacterial Meningitis Surveillance Network-initiated surveillance process aimed at Haemophilus influenza type b to perform surveillance on pneumococcal diseases. A total of 119 H. influenzae isolates from children aged >2 years but <5 years of age have been confirmed. Eighty-three isolates (69.75%) were serotype b, 19 belonged to other capsular antigen groups, and 17 were nontypable. For Streptococcus pneumoniae, a total of 442 isolates were confirmed to be pneumococci; 302 isolates were from blood cultures, and 140 were from cultures of cerebrospinal fluid. Most of the isolates were obtained from patients in the 6-29-month age group; in this age group, overall coverage by the heptavalent vaccine was 56% (increasing to 67% with the addition of cross-protection due to serotype 6A). S. pneumoniae isolates are susceptible to most commonly used antibiotics, with the exception of trimethoprim-sulfamethoxazole, and have exhibited no resistance to penicillin. A surveillance network is in place to provide local data on the importance of S. pneumoniae as a cause of both meningitis and bacteremia. Serotypes in the currently available heptavalent conjugate pneumococcal vaccine and related serotypes account for two-thirds of invasive pneumococcal disease among children aged 6-29 months.

Figure 1

Proportion of disease due to serotypes 1 & 5