PLACENTAL-TRANSFER OF MATERNAL POLIOVIRUS ANTIBODIES IN FULL-TERM ANDPRETERM INFANTS

This study was designed to investigate the placental transfer of mater nal poliovirus antibodies in full-term and pre-term infants. Two hundr ed healthy, Israeli born mothers and their infants, were enrolled imme diately after birth. The study population comprised two groups: a full -term group of 150 mothers and their infants, and a pre-term group of 50 mothers and their infants (gestational age <35 weeks), Maternal and umbilical cord blood samples were taken in all cases, Antibody titers against tile three poliovirus serotypes and a polio virus type 1 stra in that caused an outbreak in 1988 (epidemic strain 1) were measured b y a microneutralization system. The proportion of individuals with pro tective titers against each of the poliovirus types tested was slightl y lower in the infants compared with their mothers, When protection to all strains combined was tested the difference between mothers and in fants was significant (P < 0.05). Transplacental transfer to epidemic strain 1 was less effective-22% of the premature infants were not prot ected against it at birth. The geometric mean titers against polioviru s types 1, 3 and epidemic type 1 strain were significantly lower in th e pre-term group than in the full-term group. In both the full-term an d pre-term groups there were significant linear correlations between t he material and neonatal antibody titers for Each of the polio viruses tested, For all poliovirus types, the transfer of maternal antibodies to the full-term infant was significantly higher than the transfer of maternal antibodies to the pre-term infant (P < 0.001). Owing to dimi nished transfer of maternal antibodies, pre-term infants are at greate r risk of poliovirus infection. (C) 1997 Elsevier Science Ltd. All rig hts reserved.