Invasive pneumococcal disease and 7-valent pneumococcal conjugate vaccine, the Netherlands

Abstract

In the Netherlands, the national immunization program includes 7-valent pneumococcal conjugate vaccine (PCV7) for all newborns born after April 1, 2006. We compared the incidence of invasive pneumococcal disease (IPD) and patient and disease characteristics before PCV7 introduction (June 2004-June 2006) with those after PCV7 introduction (June 2008-June 2010). Culture-confirmed IPD cases were identified by 9 sentinel laboratories covering ≈25% of the Dutch population. Significant declines in overall IPD incidence were observed in children <2 (60%) and in persons >65 (13%) years of age. A trend toward gradual increases in non-PCV7 serotype IPD infections was observed in all age groups; the largest increases were among persons 50-64 (37%) and >65 (25%) years of age. In adults, the proportion of immunocompromised persons increased among IPD patients. Overall, deaths from IPD decreased from 16% to 12% because of a lower case-fatality rate for persons with non-PCV7 serotype IPD.

Figure

Serotype distribution of invasive pneumococcal disease in the Netherlands before and after (early and late) introduction of the 7-valent pneumococcal conjugate vaccine (PCV7). The 7 vaccine serotypes and the most prevalent nonvaccine serotypes are shown. The cases represent case-patients included in the study (covering ≈25% of the Dutch population). Gray, pre-implementation period (June 2004–May 2006); white, early post-implementation period (June 2006–May 2008); black, late post-implementation period (June 2008–May 2010); *Significant difference (p<0.05) between pre- and post-implementation periods, calculated by the incidence rate ratio.