Epidemiology of Invasive Pneumococcal Disease

To the Editor-Davidson et al. [I] reported a higher incidence of invasive pneumococcal disease in native Alaskans than in nonnatives.The relatively high prevalence of predisposing underlying conditions in the same group may in part explain the higher incidence of invasive pneumococcal disease in natives.However, the study did not match groups to control for socioeconomic status and the density of living, even though overcrowding is a recognized risk factor for the transmission of pneumococcal disease.As the authors correctly pointed out, the incidence of invasive pneumococcal disease must have been grossly underestimated.In addition, it is inconceivable that cases of pneumococcal meningitis were completely and uniformly reported, particularly when it was not possible to do regular blood cultures or cerebrospinal fluid analysis in the remote areas before the commencement of empiric antibiotic treatment.Of those with vaccine failure, 9 of 10 pneumococcal isolates