SYSTEMIC AND MUCOSAL IMMUNE-RESPONSE TO POLIO VACCINATION WITH ADDITIONAL DOSE IN NEWBORN PERIOD

Administration of supplementary dose of oral polio vaccine (OPV) durin g neonatal period Is recommended by WHO in countries like India, where host response to the regular three-dose schedule is not satisfactory and poliomyelitis continues to be a problem. The efficacy of this dose , +3, and +5 doses of OPV in terms of seropositivity, seroconversion, systemic, and mucosal antibody responses were measured in 51 infants i n a follow-up study from birth to 30 weeks. Administration of the addi tional dose in the newborn period significantly improved seropositivit y and seroconversion rates compared to the conventional 3 or 5 dose sc hedules. Systemic antibody titres improved with each dose of the vacci ne and 40-60 per cent of infants had >1:128 titres to the three types of polioviruses that could prevent re-infection of the gut and 50 per cent of them had mucosal antibodies as evidenced by specific IgA in na sopharyngeal secretions. Therefore, administration of OPV in the neona tal period should be made compulsory in countries where poliomyelitis still continues to be a problem.