Epidemiological serosurvey of poliovirus in Guangdong, China: A cross-sectional study.

A cross-sectional study for poliovirus seroprevalence in Guangdong was carried out in 2014, just before a change in polio vaccine commenced in 2015. The aim of the study was to test whether polio immunity level was high enough to satisfy the polio vaccine switch. A total of 6339 people were tested for poliovirus neutralization antibodies (NA). Overall NA seropositivity for PV1, PV2 and PV3 were 95.2%, 94.9% and 88.7%, and the respective geometric mean titer (GMT) were 82.9, 55.8, and 26.3, respectively. There were statistically significant differences in the positive rates and GMT of the 3 serotypes and PV3 had relatively lower positive rates and GMT. The highest seropositivity and GMT were observed in the 1-9 year-old age group. The positive rates of NA and GMT for PV1, PV2 and PV3 in the western region of Guangdong were lower than those of other three regions. The results of this study showed that the population of Guangdong province had a high polio immunity level, a stable base for a polio vaccine switch.