The graphs in this article (showing disease incidence over time relating to several diseases and several countries) make a compelling case for vaccine effectiveness.
Proponents of the anti-vaccine movement will often plot death rates over time as “proof” that vaccines were introduced at a time when they had a negligible effect. However, mortality rates are the incorrect metric when evaluating vaccine effectiveness. Here’s why:
Disease incidence is the correct metric. Since vaccines are designed to prevent the incidence of disease, rates of disease (morbidity) are the correct metric for evaluating vaccine effectiveness. If vaccines were a drug to treat disease, then case-fatality rates would be the correct metric for evaluation. Measuring vaccine effectiveness by looking at mortality rates only is a bit like measuring contraceptive effectiveness by measuring abortion rates only