An epidemiological analysis was carried out on 898 children, in order to study the immune response to polioviruses 1, 2 and 3 by means of the measurement of neutralising antibodies. Information was obtained from 522 (58.1%) of the children with regard to their vaccinal position by examination of the observations recorded on the individual vaccination certificates. In this subgroup the immune status in relation to number of Sabin type oral vaccine doses was analysed. The analysis demonstrated a high proportion of protected children for three types of polivirus, but also an immune response failure among the children of less than one year old, mainly during the first semester after birth. There were no relevant differences in relation to the proportion of protected individuals according to the considered serotype. The need for persistent and continuous vigilance in view of the possible occurence of epidemic outbreaks in high risk segments of the population, principally among children under one year of age was emphasized.
Poliomyelitis; Soroepidemiological survey; Prophylaxis; Epidemiological surveillance