If an association exists, they conclude, it must be minuscule. These results conflict with an earlier report from the Institute of Medicine, which suggested, while acknowledging limitations in data, that an association is possible. However, as the authors acknow- ledge, their conclusions are limited by sample size, and a far more expensive study would be needed to narrow the confidence intervals. However, one person's floor is another person's ceiling. What to one is an acceptable risk, given the benefit, to another may be unacceptable.
Lives hang in the balance.
Both the benefits and the risks of immunization must be measured with societal yardsticks as well as thorough epidemiological work. The continued success of childhood immunization programs rests on the public's trust. We must honor that trust by maintaining our diligence in monitoring vaccine lots and responding to adverse events. Messages to parents must be comprehensible and trustworthy, enabling parents to have confidence that existing vaccines are safe, that whatever risk exists is negligible, and that the risk is far outweighed by the personal and societal benefits. By all accounts, most parents do believe these things.