The effect of routine vaccination on invasive pneumococcal infections in Canadian children, Immunization Monitoring Program, Active 2000–2007

Active surveillance was conducted by the 12 centers of the Canadian Immunization Monitoring Program, Active from 2000–2007 in children 16 years of age and younger to determine the influence of 7-valent pneumococcal conjugate immunization programs on the prevalence, serotype and antibiotic resistance patterns of invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae. The absolute number of reported IPD cases decreased 48% (p < 0.01) over the 8-year period and 56% (p < 0.01) in children 0–4 years of age. The absolute number of reported IPD cases caused by serotypes in the conjugate vaccine decreased 87.5% (p < 0.01) overall and 92% (p < 0.01) in children 0–4 years. Although 6 non-vaccine serotypes increased over time, only serotype 19A increased significantly (p < 0.01). Overall, the proportion of penicillin resistant isolates remained unchanged at 17%. Cefotaxime/ceftriaxone resistance remained unchanged at 2% of isolates annually. Universal pneumococcal conjugate infant immunization programs have dramatically decreased cases of invasive pneumococcal disease.