Changes in poliovirus neutralizing antibodies among puerperas and infants: a longitudinal study

Objective To study variant characteristics of poliomyelitis neutralizing antibody among puerperas and their infants and to compare serological responses of different poliomyelitis vaccination schedules in the infants. Methods We conducted a longitudinal seroepidemiologic study among puerperas and their infants at Liwan District Maternal and Child Health Care Center in Guangzhou city from July 2013 to April 2014.The level of poliomyelitis neutralizing antibody of the puerperas and their infants at the birth, 3-month, and 6-month were determined and the antibody levels of the infants after oral polio vaccine (OPV), inactivated polio vaccine (IPV), and OPV plus IPV vaccination were compared. Results We collected 179, 176, 149, and 62 blood sample from the puerperas, the newborn, the infants of 3- and 6-month after the birth.There were no significant differences in demographic characteristics among the infants with OPV, IPV, and IPV plus OPV.The levels of antibody against poliovirus type I, II, and III in the newborns were lower than those of the puerperas;the levels raised rapidly with the increment of age among the infants and the values of geometric mean reciprocal titre (GMRT)of the antibody against poliovirus type I, II, and III reached up to 607.0 (95%confidence interval:146.0-2 523.1), 239.6 (80.4-713.6), and 235.9 (56.0-994.8), respectively, among the infants of 6 months old.We found no significant differences in the GMRT values and antibody positive rate among the infants with OPV, IPV, and IPV plus OPV vaccination at different time after the birth (P > 0.05 for all).The poliovirus antibody level of the puerperas was positively correlated with the levels of antibody against poliovirus type II and III of their infants(t_II=5.953, P=0.000 and t_III=7.260, P < 0.001). Conclusion The level of maternal poliovirus antibody in infants is lower than that in the puerperas.Both full course IPV and sequential IPV plus OPV vaccination have effective immune effect and sequential IPV plus OPV vaccination could be promoted at present in China.