IMMUNE STATUS OF CHILDREN TWO MONTHS TO SIX YEARS OLD TO POLIOVIRUSES I, II AND III INA RURAL AREA OF TEHRAN RELATED TO HISTORY OF VACCINATION

Abstract

A serum survey was conducted to determine the immune status of children 2 months to 6 Years old to polio virus type I, II and III related to the history of oral polio vaccination in Fashapouye (A rural area in the south of Teheran). 566 serum samples were obtained from children in 9 different villages and microneutra lization test was performed on 1;10 dilution of these sera. The study revealed that 62 per cent had received three or more doses of vaccine, 8.3 per cent two doses, 13 per cent one dose 5.6 per cent were not vaccinated. On the entire study group prevalence of immunity (serum titer 1; 10) irrespective to the history of vaccination was 90, 94 and 86 per cent for polio I, II and III respectively. The highest rate of unvaccinated and nonimmune children was in 2 to 6 months old group. The percentage of children lacking antibody to polio, I, II and III in nonvaccinated is 41, 25 and 34 percent respectively and these rates decrease in vaccinated children to reach the level of 6, 2 and 10 percent in those who have received three or more doses of vaccine. Over all results suggest that an adequate response to oral polio vaccination is observed in this rural region but an increased effort must be made for covering a higher percentage of children in all age groups especially in 2 months to one year old.