Trial of high-titre human rubella immunoglobulin

To test the efficacy of passive antibody for protecting susceptible pregnant women who have been exposed to rubella high-titre human rubella immunoglobulin (HRI) was given to 20 seronegative male adult volunteers simultaneously with rubella vaccine. After receiving the intramuscular injections of HRI (750 mg of IgG) and vaccine (10(3 . 92) median tissue culture dose, Wistar RA27/3 subcutaneously) eight of the 20 volunteers failed to show seroconversion. Antibody responses--and thus presumably viraemia--in the remaining 12 volunteers were delayed and reduced when compared with those in 19 volunteers given the vaccine alone. No significant responses occurred in volunteers given only HRI. We conclude that HRI may be of value for seronegative pregnant women who come into contact with clinical rubella, particularly when termination is likely to be refused.