[Passive immunization against rubella: studies on the effectiveness of rubella-immunoglobulin after intranasal...

The effectiveness of high-titre rubella immunoglobulin was tested on rubella-susceptible female juveniles or young adults after intranasal immunization with rubella strain RA 27/3, 20 ml of rubella immunoglobulin having been administered intramuscularly to 56 subjects at different times (1, 3 and 5 days) after the immunization. The effect was demonstrated by seroconversion and virus isolation from the throat. In the control subjects (26) the secroconversion was 96% and in 42% of subjects virus was demonstrated in the throat. Early administration of rubella immunoglobulin (up to three days after immunization) depressed the seroconversion rate to 55% and virus isolation rate to 17.5%. Later administration (five days after immunization) increased the conversion rate to 81%, the isolation rate to 31%. There were no serious side effects of the immunization and the injection of the immunoglobulin. The results indicate that on early administration of an adequate amount of high-titre rubella immunoglobulin a protective effect can be expected, although this favourable effect-obtained in the conditions of this study-cannot be unreservedly transposed to the situation in wild virus infections.