With polio on the rise and proportionately more paralytic cases in 1959 than in any year since vaccinations became general, the National Foundation determined to nail down the vaccine's effectiveness. Last week it announced the encouraging results of a check on the year's first 624 cases in which detailed vaccination histories were available. Of the 4.9 million children under five (the most susceptible age group) who had received no Salk shots, 298 got paralytic polio, for a rate of 6 per 100,000. Of the 10.4 million who had had three or more shots, only 52 got paralytic polio, for a rate...
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