Epidemiology of poliomyelitis in Israel, 1952-59, with evaluation of Salk vaccination during a three-year period.

The epidemic of poliomyelitis which occurred in Israel in 1958 among a population a large proportion of which had received inactivated Salk-type vaccine aroused great interest. This was the first time a vaccinated infant population had been exposed to a severe epidemic and thus afforded the first opportunity to determine whether or not vaccination afforded a high degree of protection in this age-group. The authors report on the observations made.While the vaccine conferred some protection, this was not of so high a degree as had been expected from experience elsewhere in older children. This partial failure may be explained in part by the use in the earlier vaccination campaigns of vaccines of lower potency than is now current and perhaps by the fact that many vaccinations were performed intradermally.No very exact measure of the protection conferred can be given. For some groups the figures are too small for statistical validity; for others, it is not possible to distinguish between the effect of vaccine and that of age, the latter possibly being the more important factor.