Studies of the effect of immunoglobulin on rubella in pregnancy. Report of the Public Health Laboratory Service Working Party on rubella.

Studies were done on 5,447 pregnant women given immunoglobulin after exposure to rubella and on 652 adult women similarly at risk but not pregnant and therefore not given immunoglobulin. The amounts of immunoglobulin, of known antibody content ranged from 750 mg. to more than 1,500 mg.; in a few second doses were given. Preinoculation blood samples from both groups showed that about 15% were still susceptible. Second blood samples were obtained from many of the women and nasal and throat swabs from as many index cases as possible. In the development of rubella by susceptible women a major factor was an index case in the same household. Whether judged on the serological evidence alone, or as a result of exposure to a confirmed index case, immunoglobulin in the amounts given did not appear to affect the incidence of rubella by comparison with the uninoculated group. Suppression of clinical manifestations attributable to immunoglobulin was possible in a few instances, but this could also have been an example of natural variation.