Fetal risk associated with rubella vaccine: an update.
One hundred nineteen women susceptible to rubella received RA27/3 vaccine, 94 received either Cendehill or HPV-77 vaccine, and one received a vaccine of unknown strain in the three months before or after their estimated date of conception. They gave birth to 216 living infants free of abnormalities compatible with the congenital rubella syndrome (CRS). The maximum theoretical risk for CRS for these infants was 1.7%. Four of these infants born to susceptible women had laboratory evidence of subclinical infection (three after receiving Cendehill or HPV-77 vaccines and one after receiving RA27/3 vaccine) but were normal at birth and at subsequent follow-up examinations. Rubella virus was isolated from the products of conception for only 3% (1 of 32) of cases involving susceptible women who received RA27/3 vaccine; the reported rate of virus isolation for Cendehill and HPV-77 vaccine is 20%. The available data indicate that if vaccination occurs within three months of conception, the risk is negligible. However, since the actual risk may not be zero, women known to be pregnant should not be vaccinated, and conception should be avoided for three months after vaccination.