Protective effect of antiribella human immunoglobulin

Previous experience with immune serum globulin (ISG) indicated 1) that it did not prevent viremia in children with rubella infection, and 2) that it did not prevent congenital rubella. This report describes the protective effect of an experimental lot of high titer antirubella human immunoglobulin (RIG) in 33 children exposed to the Brown strain of rubella virus (RV). RIG was given to 22 of the susceptible children 24 or 96 hours after intranasal exposure to RV. Six other children received ISG. The dose of RV was either 104TCInD50 or 101TCInD50, and the dose of immunoglobulin was 0.3 ml/kg of body weight. In the group that received RIG: 1) passively acquired rubella antibody was detected transiently after inoculation in 15 children; 2) no detectable viremia was observed; 3) pharyngeal shedding of RV was decreased and 4) the rubella specific IgM response was depressed. RIG was more effective when given at 24 hours against low dose virus challenge, preventing or delaying seroconversion; it was less effective in modifying infection when given at 96 hours after high dose challenge. These data suggest that RIG may be useful for the prevention of congenital rubella.