[Surveillance of levels of neutralizing antibodies against poliovirus among children aged 0-3 in rural areas of Anhui Province].

Levels of neutralizing antibodies against poliovirus (PV) in 1,755 children aged 0-3 sampled randomly from 18 counties in Anhui Province were determined in September, 1993. Results showed the positive rates and geometric mean titer (GMT) of neutralizing antibodies against PV type 1, 2 and 3 were 96.98%, 96.01% and 96.18%, and 524.80, 323.59 and 436.50, respectively. Immune level of children was considerable high in each county sampled. No significant difference was found among different age groups and between boys and girls in positive rates and GMT of polioantibodies, but there was significant difference in them between children administered varied doses of oral polio vaccine (OPV). Children investigated took four doses of OPV in average, and their GMT was in proportion to the dose they took. Positive rate of PV antibodies was more than 95% in children who finished the full course of OPV immunization. There were very few townships or villages with a low coverage of OPV immunization in children. It indicated polio immune status was in a higher level in the Province.