Decreasing invasive pneumococcal disease in the elderly: a state-level analysis.

Evidence has accumulated supporting the relationship between the use of 7-valent pneumococcal conjugate vaccine (PCV7) in children and a decline in invasive pneumococcal disease (IPD) in the elderly. We conducted a state-level analysis of vaccination coverage rates among children 19-35 months of age and IPD hospitalization rates among elderly Medicare beneficiaries. Simple correlations were suggestive of a negative relationship. Multivariate analysis using a state fixed-effect model which helped control for the time invariant factors at the state level also indicated a negative relationship, and it was statistically significant, p = 0.035. The relationship between the use of 23-valent pneumococcal polysaccharide vaccine (PPV23) and IPD hospitalizations was not statistically significant using either method.