Osman Abdullahi

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BACKGROUND Transmission and nasopharyngeal colonization are necessary steps en route to invasive pneumococcal or Haemophilus influenzae disease but their patterns vary geographically. In East Africa we do not know how these pathogens are transmitted between population subgroups nor which serotypes circulate commonly. METHODS We did 2 cross-sectional(More)
BACKGROUND To understand and model the impact of pneumococcal conjugate vaccines at the population level, we need to know the transmission dynamics of individual pneumococcal serotypes. We estimated serotype-specific clearance and acquisition rates of nasopharyngeal colonization among Kenyan children. METHODS Children aged 3-59 months who were identified(More)
BACKGROUND Pneumococcal conjugate vaccines (PCV) reduce nasopharyngeal carriage of vaccine-serotype pneumococci but increase in the carriage of non-vaccine serotypes. We studied the epidemiology of carriage among children 3-59 months old before vaccine introduction in Kilifi, Kenya. METHODS In a rolling cross-sectional study from October 2006 to December(More)
BACKGROUND There are more than 90 serotypes of Streptococcus pneumoniae, with varying biologic and epidemiologic properties. Animal studies suggest that carriage induces an acquired immune response that reduces duration of colonization in a nonserotype-specific fashion. METHODS We studied pneumococcal nasopharyngeal carriage longitudinally in Kenyan(More)
We compared nasopharyngeal swabs against nasal wash cultures for detecting colonizing pneumococci and examined the effect of frozen storage in skim milk-tryptone-glucose-glycerin on culture. Among the 55 children with positive nasal wash cultures, swab cultures were positive for 47 (85%). Of the 96 swabs positive on direct plating, 94 (98%) were positive(More)
BACKGROUND Herd protection and serotype replacement disease following introduction of pneumococcal conjugate vaccine (PCV) are attributable to the vaccine's impact on colonization. Prior to vaccine introduction in Kenya, we did an epidemiological study to estimate the rate of pneumococcal acquisition, by serotype, in an uncolonized population. METHODS(More)
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