Unresolved issues in the first five years of the rubella immunization program.

Despite extensive use of atttenuated rubella vaccine during the past five years, the degree of fetal risk in susceptible women inoculated early in pregnancy is still an unresolved issue. Although there is considerable evidence of chronic vaccine virus infection of the products of gestation in aborted fetuses, congenital defects have not yet been reported in the newborn infants of susceptible vaccinated pregnant women. The normal findings in the newborn infant can be misleading with respect to the safety of the vaccines in early pregnancy, because they represent only a small selected group of reported cases. The immediate need is for more complete reporting of all relevant cases wherever they occur in order to determine without many more years of delay whether the fetal risk has public health significance or is so low as to be of negligible importance.