Hospitalizations after a Decade of Pneumococcal Vaccination

To the Editor: Griffin and colleagues (July 11 issue)(1) report a reduction in the incidence of pneumonia after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7). The authors address the concern regarding serotype replacement, whereby a vaccine-mediated reduction in the disease burden of Streptococcus pneumoniae PCV7 serotypes is offset by a proportional increase in nonvaccine serotypes. However, species replacement by other pathogens, particularly Staphylococcus aureus, is equally troubling.(2) There has been an increasing incidence of S. aureus infections in the United States since the widespread adoption of PCV7.(3) According to Gause's law of competitive exclusion, bacteria compete for resources ...