In Reply.—Dr Bader's thoughtful comments merit consideration now and for the future. If, indeed, the state of Washington has a vaccine-associated paralytic polio rate of 1 per 100 000, it differs markedly from the rest of the nation where careful surveillance and annual review of reported alleged cases by an expert committee have consistently disclosed an overall rate of 1 per 2.7 million poliovirus vaccine live oral trivalent (TOPV) doses or 1 per 560 000 first doses of TOPV. From 1975 to 1986, 107 cases were labeled vaccine-associated paralytic disease, of which 37 were in recipients and 48 in contacts. If Washington has a higher rate, it may resemble the unexplained geographic (or possibly genetic) aberrations observed in some other infectious diseases studies such as the unusual results in Minnesota with the initial studies of Haemophilus influenzae type B polyribose phosphate vaccines in contrast to the efficacy studies in