Reinoculations of Poliomyelitis Vaccine

To the Editor:— I have had a number of inquiries concerning the question of reinoculations in children who received poliomyelitis vaccine during the 1954 field trial. I intend to discuss this subject, in relation to the broader problem of degree and duration of vaccine effectiveness, at the Annual Meeting of the American Medical Association in Chicago in June. However, the date of publication of that report will be too late to provide guidance for physicians before the 1956 season. Therefore, I thought it might be helpful to outline certain thoughts that bear on this question. It will be recalled that Dr. Francis found vaccination, as performed in the field trial, and using the particular preparations then available, to be effective in 60% or more of those exposed to a potentially paralytic infection. We might reason, therefore, that there remain, in the group of field trial children, approximately 40% or less