Immunity status to poliomyelitis of 0-12 years old children living in S. Paulo city, Brazil and using the Menino Jesus Hospital

Abstract

The prevalence of neutralizing antibodies for the three types of polioviruses and the immunity levels of different age groups were determined through a seroepidemiological survey, in a population of 0 to 12 year old children, living in the city of S. Paulo and attending the Menino Jesus Hospital. The results showed a high number of children susceptible to infection by polioviruses, mainly in the 9-12 month age bracket where the proportion of individuals completeley susceptible was 42.5%. In this group the prevalence of type 1, 2 and 3 antibodies was only about 40%. For the 0-5 year old children only 60% were found to be double plus triple immune, among those who got three or more doses of oral trivalent vaccine. The results also showed that the immunity status of the children in this group was the same in the three geographical zones of city of S. Paulo, there being abount 50% of double plus triple immune children. These results show low levels of immunity mainly for those in the first year of life. These is then a clear necessity for new serological surveys, besides intensification and improving of routine vaccination against poliomyelitis in our region.