Analysis of the poliomyelitis situation in the city of S. Paulo, Brazil by means of an epidemiologic surveillance parameter

Abstract

The situation of poliomyelitis in the city of São Paulo is analysed by means of an epidemiologic surveillance parameter - the "r" factor of immunization events. The results of a recent sero-epidemiologic survey realized in this City were transformed into the catalytic growth curve y = a + (1 - a) (1 - e-rt). The informative value of the survey is therefore considerably enhanced. The analysis showed that about 50% and 60% of the population of children 0-10 years old were immunized by oral polio vaccination against type 1 and 2 polioviruses, respectivilly-Further, the average rate of effective contacts between individuals of the entire population and type 1 and 2 polioviruses were, per annum, respectively 85 and 70 per 1000 inhabitants. Due to the relative high mortality rate to poliomyelitis for children of the first year of life (31 cases per 100.000), it is emphasized that children must receive oral vaccine at 2 or 3 month of age.