It should be emphasized that reports of nervous system illness following mumps vaccination do not necessarily denote an etiologic relationship between the illness and the vaccine. The frequency of reported CNS dysfunction following mumps vaccination is lower than the observed background incidence rate of CNS dysfunction in the normal population. Although mumps virus is capable of infecting the placenta and fetus, there is no good evidence that it causes congenital malformations in humans. Mumps vaccine virus also has been shown to infect the placenta, but the virus has not been isolated from the fetal tissues from susceptible women who were vaccinated and underwent elective abortions. However, because of the theoretical risk of fetal damage, it is prudent to avoid giving mumps vaccine to pregnant women.
Allergies Live mumps vaccine is produced in chick-embryo cell culture.
Evidence indicates that persons are not at increased risk if they have egg allergies that are not anaphylactic in nature. Such persons may be vaccinated in the usual manner. There is no evidence to indicate that persons with allergies to chickens or feathers are at increased risk of reaction to the vaccine. In such individuals, the adverse reaction, if any, to 25 ug of neomycin in the vaccine would be an erythematous, pruritic nodule or papule at 48-96 hours. A history of contact dermatitis to neomycin is not a contraindication to receiving mumps vaccine.