Optimum age of a child for BCG vaccination.

The objectives of this study were to evaluate whether a newborn or a neonate is capable of responding immunologically after BCG vaccination and to find out if this immunity persists for one year. Normal infants aged between 0 days-3 months brought to immunization centre were included in the study. In vitro leukocyte migration inhibition test was performed in these children using Phytohemagglutinin and purified protein derivative (PPD). They were grouped based on their age at vaccination, their LMI values and on the time interval after vaccination. The mean values of % LMI (PPD) in all the age groups were positive and there were no significant differences between the newborns, the neonates and other groups. The values were positive and comparable even after 12 months in all the groups. The percentage of infants with positive or negative values to LMI (PHA) and negative values to LMI (PPD) were also comparable at different time intervals in different age groups. The results suggest that newborns or neonates are as capable of eliciting a positive immune response after BCG vaccination, as older infants and the practise of vaccinating a child at birth could be continued.